my two cents

GLK: test drove for 20 minutes: it looks good (better than ML model). It's small-size SUV with small interior space. Very agile but lack of power from my perspective, might be a good fit for female driver. Overall, I'd go with a sedan with 4-wheel drive and more horsepower.

Volvo XC 90: never drove one, has no idea. Although it looks good - I like the style.

BMW X5: drove a 2002 X5 v8 4.4 for 7 years; drove couple x5 v6 3.0 loaners when my x5 in the shop. Outstanding driving experiences, but visited the shop too many times, especially after the warranty expired. Pre-certified should give you extended warranty - two more years with twenty thousands more miles? If you really like it, go with it, but remember to get rid of it prior the expiration.

Highlander: never drove one, has no idea. It looks ugly, though.