This is a good way to get free international roaming to customers. I don't see why it takes so long to get to other devices other then its an intergrated app instead of simply a Sprint app from the Play Store, but if they can get ir quickly to all phones its not a problem.
...That will work with any smartphone. I use Groove IP. It's free and allows users to call, even from WiFi-only tablets. You can set up this app to work with your existing number, as well, via Google Voice.
Google no longer allows usage of third party apps to use your google voice number. This is why Talkatone made their own service. Also the quality difference on sprints wi-fi calling oppose to VIOP calling is worlds apart. Also you'll be using your own... (continues)