Long story short, I went from 2 phones to 1. I moved my main phone number to Google Voice.
There are a number of Apps (GrooveIP, Sipdroid, and Talkaround) that use data to talk with Google Voice. In each case, by default it works on WiFi only, but you can upgrade/change options to let it use the 3G/4G data.
I have used each app on FAST wi-fi only, and the voice quality is horrible. I have tried adjusting settings, but haven't found a set that would work well. It could be that I haven't found the right one.
In addition, I have found that Talkaround really slows my phone down through heavy use of resources.
Have any of you had any success at doing what I wanting to do? If so, if you could share some "how-to," that would be great!
Thanks so much!