要與voip.ms比一下。。。

voip.ms (price in USD, calling out)
US --- 1c/min (300min => $3)
US Hawaii --- 1.63c/min
US Alaska --- 3.17c/min
Canada --- most areas are 0.5c/min
China --- most areas are less than 1.3c/min (60min => $0.78)

$3+$0.78 = $3.78 for the same service.

Also voip.ms call duration count is in 6 seconds increment.  Most other providers are in 1 min increment.

Calling in --- since you have GV and OBi device, you can apply for a free DID (say, from IPKall) to get free inbound calls.

Not sure if Phone Power will add additional charge for 911 and other taxes/fees.