Before proceeding, grab a coffee as this is a long one. It's broken down into major categories so that you may skip to those that interest you.
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SIZE, ROOM, AND CARGO
Exterior: RX is over 5" longer and a couple inches wider and taller, with a 3"+ greater wheelbase. These few lesser inches makes the NX easier to park in my garage allowing for better front/rear clearance resulting in a worry-free opening of the rear hatch.
Interior: RX has 1" more front/rear combined legroom, less than 1 in more headroom, and about 2" greater seating width. Three child seats or adults fit well in the RX's rear bench while three in a pinch in the NX. Front seat room is roomier in the RX also due to a less intruding dash and console.
Cargo: RX totals 40/80 seats up/down vs 18/54 cu ft. My calculations show 28-30 cu ft based on this post here. As for usable cargo, 4 grocery bins fit in the NX while 5 fit in the RX with not much else. However, there is still space in the NX to fit two large and two small grocery bags almost equaling the square footage of the RX's. RX has the 40/20/40 split rear seat while the NX is limited to a typical 60/40 configuration. In addition, two handles exist in the trunk in the RX to drop the seats while none exist there for the NX. (Power rear folding seats available on certain NX models controllable by the driver, passengers, and from the trunk). RX rear seats also slide several inches fore/aft for added cargo flexibility at the expense of decreased legroom.
OVERALL: RX wins this category thanks to its midsize CUV dimensions.
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POWERTRAIN RESPONSIVENESS AND POWER
Standing start acceleration: At part throttle, the RX responds more quickly thanks to a more responsive 8-speed transmission, V6 torque, and slightly firmer feel of the pedal. Throttle tip-in/response is quicker on the RX even compared to the NX's Sport S or S+ setting. Transmission shifts from first to second to third are smoother on the NX over the RX's but at the cost of a slower launch and slower shifts. At full throttle, the RX has a fractionally better launch but the NX quickly builds power and is quicker 0-60 mph by 0.7 secs. At full throttle, NX transmission shifts are less sluggish though still not as quick as the closer-ratio RX 8-speed.
Passing: NX in Normal or Eco is less responsive to a downshift and the mushy pedal exacerbates the somewhat sluggish feel. To get a proper kickdown and passing power, greater throttle input is required on the NX unless you are in Sport S or S+ mode which then feels similar to the RX.
Manual Mode: both the RX and NX require the engine/transmission to reach proper operating temperatures before full manual control is possible. Thanks to the RX's additional cogs, the shift time is quicker in M-mode also, though slightly less smooth than the NX's.
Special Note 1: as the marketing videos mention, the NX Turbo's power delivery is linear in feel and not laggy with a sudden surge like older turbos or with some competitors'. In short, more throttle = eventually the feel of more power than the RX.
Special Note 2: when engaging Reverse, the RX must be fully stopped first or the the slightest forward motion will result in a jerking thump. The NX can be
put in Reverse smoothly even while it's still moving slightly forward.
OVERALL: RX wins by a slight margin thanks to its more readily available, usable, and more responsive power delivery with less throttle input. However, in a drag race, or if you have a naturally heavy foot, the NX will easily win.
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NVH (NOISE, VIBRATION, HARSHNESS)
Tire/road noise: both similarly fairly low at highway speeds. Note, the NX has triple-seal doors which contributes to reduced road noise equaling that of the RX. The RX does not have this.
Engine noise: although engine sounds are different, the NX's 4-cyl Turbo is surprisingly a touch quieter than the RX's V6, even under full throttle. The NX's Turbo sounds less throaty and more sophisticated than the RX's V6 thanks to the faint Turbo "smooth sewing machine-like" whine in the background. Note, unlike US F-Sports, no Active Sound Control is available on Canadian models.
Wind noise: RX is slightly better. On the NX, slightly more wind buffeting noise is heard around the driver's window/mirror likely due to single-pane windows vs Lamisafe double-pane windows on the RX.
Engine smoothness/vibrations: NX's 4-cyl Turbo is surprisingly smooth and vibration-free across the entire powerband, arguably smoother than the RX's V6. However, under a specific set of conditions, uncharacteristic to Lexus, the 4-cyl vibrates on idle - engine temp about 1/4, HVAC on, engine RPMs at 750-800, in D, and brake pedal fully depressed (i.e. at a red light). Remove one or more of these conditions (i.e., warmer engine temp), and engine idle is smooth.
OVERALL: Tie.
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RIDE QUALITY
Over small road imperfections: NX and RX are equally smooth thanks in part to both vehicles equipped with front/rear lateral performance dampers.
Over larger imperfections and speed bumps: Surprisingly, the NX is smoother than RX. Initial impact is better absorbed and rebound better controlled especially in sub-freezing temperatures where the RX's shocks and absorption is notably harsher. The NX, less so, this despite a shorter wheelbase.
Hwy ride: NX as smooth as RX.
Special Note 1: My NX is equipped with AVS (Adaptive Variable Suspension) designed to better absorb bumps and control motion. In N.A., as of this writing, this is only available in Canada on the F-Sport Series 2 package.
Special Note 2: Having switched to larger (though lighter) 20" rims and fatter lower profile 255/45/20 Yokohama Parada Spec X A/S tires, this change has had no perceptible negative impact to ride comfort compared to the OEM 225/60/18 Michelin MXM4 tires.
OVERALL: Surprisingly, the NX wins this category thanks to a more polished, composed, smoother ride that gives the feeling you're floating over the road. It's possible this is due to the AVS.
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HANDLING
Maneuverability: Similar overall. In low speed parking situations, the NX's slighly poorer visibility (taller belt line and smaller windows) and surprisingly larger turning circle (by 1 ft) is offset by the RX's larger size and bulk.
Cornering/Body Roll: NX has similar (minimal) body roll as with the RX.
Quick Transitions: NX is more nimble and lighter on its feet and "carves" more than "plows" (RX) when making quick left/right steering inputs. NX feels more secure during higher speed emergency lane changes - this is thanks to a quicker ratio steering, lower center of mass/ground clearance, and 400 lbs less mass.
Traction and Stability: Equivalent AWD traction on snow for both NX and RX thanks to similar Active Torque Control AWD systems with on-demand 4-wheel lockup. However, the VDIM (Vehicle Dynamics Integrated Management) on the RX adds an additional layer of control thanks to a small amount of proactive steering, braking, and throttle inputs to correct the driver's intended line as per driver steering, throttle, and braking inputs. NX utilizes the standard VSC, TRAC, and ABS systems reactively to control stability.
OVERALL: NX wins this category by a slight margin thanks to its more nimble and surefooted control and handling.
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SEATING AND CREATURE COMFORTS
- RX has softer and wider perforated heated and ventilated leather seats. NX's sport seats hold you snug for a sportier feel, but the stiff bolsters (bottom and back) and narrow seats can inflict discomfort after a long drive. Think soft room-temp butter (RX seats) vs harder "refrigerated" butter (NX seats).
Note: For those familiar with the IS (and RC), although the seats are similar in shape and movement control, the injected foam in the bolsters is much
firmer in the NX. Nuluxe feel and quality on the NX (like the IS) suprisingly feels softer and richer than the RX's real hide.
- RX has more foot room beneath the front seats for rear passengers. Bulky construction boots (RX) vs running shoes (NX) is the difference. Of course, the NX seats can be raised to clear a construction boot but at the detriment of front seat headroom. However, the NX's rear seat is higher for a more upright position with better thigh support for adults.
- NX's driver's position sits slightly lower (~ 1 inch) but still feels elevated like driving an SUV. However, the high bottom bolsters negate any ingress/egress benefits that would have been gained by the lower front seating.
- NX cup holders are indeed convenient for water bottles with a one-handed twist of the cap and operation thanks to its unique spring-loaded prongs and sticky bottom base. RX's is nicely covered in genuine wood but the cup holes are hard plastic however with a removable center section. RX also has the third cupholder conveniently placed by the left-side driver's vent.
- NX console is a little smaller than RX's. However, when factoring in the "secret" sub-floor console space and the cubby space beneath the transmission, RX clearly has the superior space.
- NX's felt-lined glove box is larger/deeper but hits the passenger's knees when opening. RX's is soft-touch plastic with similar felt-lined material but only inside the glovebox and not on the inner door (hard plastic).
- RX's fold-out door map pockets are superior in access, convenience, and provide a larger space for bottles, books, papers, etc. NX's is a rigid lower cubby with less space.
- NX's touch LED ceiling lights are bright and more easily accessed vs the traditional push button on the RX.
- Sun glass/mirror console cubby holds my mid-sized sun glasses, about the same as the RX's overhead sun glass holder (n/a in the US since the SOS button is there)
- Seats and engine heatup slightly quicker in NX.
- Wiper deicer is both work well yet both are cumbersome to activate via three/four clicks and navigation in the Remote Touch Interface (RTI)
- NX has a convenient dedicated physical A/C button on the HVAC controls whereas it's three/four clicks away in the RTI on the RX.
- Although the RX's 8" screen is bigger than NX's 7" screen, the RX's is further from the driver negating the benefit of the 1" larger size.
- NX's power rear hatch opens/closes slightly slower. Worse, the NX cannot be manually closed - the moment you manually apply force to close the hatch, the power mechanism engages. In contrast, you have control to either manually (quickly) close the hatch while in inclement weather or press the power door button to automatically have the RX shut the door. The only manual override for the power hatch on the NX is via a setting accessed from the steering wheel in the center 4.2" display. This requires the key fob and car to be powered electrically on. In contrast, the RX has the convenience of a physical button located in the glovebox if one wants to disable the power hatch. Both vehicles have the same power control button on the lower dash to open/close the hatch and the same two buttons on the outside hatch to open/close and to lock the doors. NX's hatch is height adjustable and can be stopped at any height. RX's either fully opens or fully closes. Both vehicles inconveniently must have their hatch closed before you can engage the door lock command.
- NX's floor carpeting and mats are of similar high quality to the RX's.
- RX's velours/felt-like headliner is more premium than the NX's coarser "polyester-like" material.
- RX's wipers and arms are more massive and provide a better more planted clean "arc-sweep" compared to the NX's simple-rotating less premium-looking and effective wipers.
- RX's power folding mirrors are not available in the NX and was convenient in tight spots and as a confirmation the RX's doors were locked.
- NX's full triple "L" LED headlights, DRLs, and fog lights with active Cornering Lights that enable in turns provides an overall brighter experience over the RX's HID/Halogen combination.
- NX and RX both have effective exterior courtesy/proximity lighting though the NX's lit handles, concealed key lock, and lock dimple (on all four handles) is more convenient. RX does however have door lights whereas the NX does not.
OVERALL: RX wins this category as the overall more comfortable and "easier to live with" vehicle.
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TECH
- NX wireless charger is convenient and charges quickly my Nokia 830 (built-in Qi wireless charging).
- NX's Remote Touch Interface with the new touchpad is a slightly improved controller over the physical mouse-like controller. However, I find the control is only better once I disabled the awkward haptic feedback eminating from the touch screen each time you move the cursor from one selection item to another.
- RX's top-end 7.1 15-speaker Nark Levinson surround sound system is richer, clearer, and more powerful than the NX's top-end 10-speaker Premium sound system, but not by much to my non-audiophile ears.
- NX's HUD (Head Up Display) is better than the RX's. Larger color display in addition to more viewable information like engine rpm, Eco bar, road speed limit, Pre-Collision and Land Departure alerts, on top of speed, radio, and GPS directions.
- NX's Rear Backup Camera is brighter with active grid lines vs the RX's plain camera.
- NX's Nav has 3D view in its map vs 2D only on the RX.
- NX has an auto electronic parking brake vs the RX's manual foot-operated one.
- My NX also has several more tech features that my particular RX did not have available: Heated SteeringWheel, Blind-Spot Monitoring w/Rear-Cross-Traffic Alert, Dynamic Radar Cruise w/Pre-Collision, Parking Assist, and Lane Departure Alert.
- NX's 4.2" center cluster high-res color display easily outshines the RX's older pixelated display and more limited information.
OVERALL: NX clearly wins this category thanks to incorporating the latest tech vs the RX's tech dating back to spring 2009.
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FUEL ECONOMY
- NX is about 20% (combined city/highway) better than the RX in fuel consumption, however some of this benefit is offset by the requirement of Premium 91 octane fuel for the NX's 2L Turbo vs the RX's Regular 87 octane fuel.
OVERALL: NX wins by a slight margin at this time since Premium fuel's price premium of 5-10% still results in about 10-15% cheaper fuel costs over the RX.
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FIT, FINISH, AND BUILD QUALITY
Exterior: Both RX and NX have equally excellent body panel gap consistency, panel and trim alignment, and top quality paint finish. However, the NX's slightly smaller door gaps are an improvement over the RX's.
Interior: Hard plastics reside in the lower doors, dash, console, and C,D pillar covers in both vehicles though the thickness and feel of the plastic is better in the RX's lower door panels vs the NX's thinner feeling (and slightly cheaper) material. The hard plastic surrounding the window switches and the switches themselves on the NX are also of slightly lesser quality than the RX's. The RX's glovebox is covered in soft plastic vs harder plastic on the NX's while the handle is also better than the NX's push-style cheaper-looking latch. However, the soft plastics in the upper door panels and dash, the Nuluxe stitched dash and HUD pad, and upper stitched door plastics is better than the soft plastic uppers in the RX. In addition, the fit and gaps in the NX are visibly better than the RX's gaps such as in the center console around the transmission and HVAC controls, driver/passenger vents.
Quality feel: HVAC and Radio button controls feel equally solid and of high quality in both vehicles, but the new turn signal and wiper stalks feel buttery smooth on the NX vs the RX's more mechanical clicking feel. The high-quality cruise control stalk is virtualy the same in both. The steering wheel is slightly larger and thicker on the RX with higher-quality looking and feeling steering wheel buttons and better quality leather vs the NX's. The console arm rest sliding feature on the RX results in a lower quality feel compared to the NX's fixed (pivot-only) padded console lid. Similarly, the RX's sliding rear seat feels less solid than the NX's fixed seat. A final indicator of build quality - the sound and feel of the door slam. The RX's is fine but the NX's is a clear step above. The front doors close with a more solid thump vs the RX's more tinny/vibrating sound and feel which is partially due to the bottom valence cover and mirror rattling when slamming the door. Rear door slam sound and feel is not as solid as the front but comparatively better than the RX's rear doors.
Squeaks and rattles: possibly not a fair comparison with the NX being new and the RX much older, however, I do recall the RX having the infamous B-pillar ticking sound and rear seat rattle in the first days of ownership. NX is rock solid so far.
OVERALL: NX wins this one thanks to a modern release of visibly better build/materials over the due-for-redesign RX.
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CLOSING STATEMENTS
While the NX is better in some categories like the ride, handling, and build quality, the RX is better in space and passenger comfort. Factor in your styling preference and budget and the choice hopefully becomes clearer. Of course, there is also the reliability factor where the Turbo is an all new engine, but Lexus' (and Toyota's) track record speaks for itself where one can confidently dismiss this "risk". A final factor not mentioned is pricing. At this time, a '15 RX can be had for almost the same price as a '15 NX which creates a whole new value proposition in favor of the RX for those seeking space and comfort over all else. Any questions, please feel free to post and thanks for reading!