Reasons why youre better off with Skype or Google Hangouts:
1. You have to watch ads and take surveys in order to call people
2. Horrible sound quality
3. I tried calling a friend in the states (I live in Canada) and there was a 10 second delay between the time I would say something and he would hear me say it. I know 2 and 3 are not due to my internet because hangouts, Skype, and teamspeak work perfectly.
POINT3L about Phone for Google Voice & GTalk, v3.0.1