My wife is travelling to Toronto, Ontario soon, with her unlocked HTC Sensation 4G, and wants the best way to voice-call and text back to me in the U.S. She'll have WiFi access at her hotel. We have the T-Mobile "World Class International Service" added to both phones. The choices appear to be the T-Mobile International roaming (at 59c/min, ), or the Talkatone or Skype for Android apps. For the VOIP options, is Google Voice a necessity for those to work? And, does GV only work in the U.S.? Appreciate the advice, thanks!
If you want to use Skype that is all you need to download. If you want Google Voice that is all you need also. You do not need one for the other to work.
Both Skype and GV will work on WiFi while the wife is in Toronto. I would go with Skype but if the connection is bad she can then switch to GV. There is nothing wrong in having both on her phone and on yours.