I’ve been looking to move from Skype to Google Voice. To save cell phone minutes (yes I’m still on a family share plan), I try to use VoIP to make calls when I have access to reliable internet. Unfortunately I the Google Voice app for iOS doesn’t support VoIP, even though it has a dialpad. This is only a callback service that uses your normal cell phone minutes. This app looks like it is on it’s way out, as it hasn’t been updated since September 2013 and hasn’t been updated with an iOS 7 look and feel.
Fortunately, the Google Hangouts app has most of the features you’d expect from a calling/video chat app. It allows you to make VoIP calls to US phone numbers for free and lets you video chat with your other Google contacts. The downside is that you still need the Google Voice app to manage a few voice settings, view missed calls, and listen to voicemails.