I'm dissatisfied with almost all VoIP apps I've tried (including Viber, but especially Skype on iOS). Is there any good alternative or are mobile connections still too finicky for satisfying VoIP?
I don't have a problem with Google Hangouts technically; the problem is it is not open (and security is questionable).
I found facetime to be pretty good even in low bandwidth situations. The only problem is it does not give me an option yet to drop the video while in a video call and revert to a audio only call. But on the whole I like it.