I don't use the official Google Voice SIP server as I didn't have a Gizmo5 account before it was shut down. I just use an sipgate.com account added to my Google

I don't use the official Google Voice SIP server as I didn't have a Gizmo5 account before it was shut down. I just use an sipgate.com account added to my Google Voice account. If you're worried about latency, you could try using the undocumented Gmail Google Voice API through GrooVe IP (https://play.google.com/store/apps/details?id=com.gvoip https://play.google.com/store/apps/details?id=com.gvoip) to get a direct connection to Google Voice.