I was just going to purchase a new Obi device for my mother and brother and came across this article ( link here ).
Recently Google announced the end of support for XMPP based calling with Google Voice. This will happen on May 15, 2014 – that’s over 6 months from today. Since your OBi device uses XMPP to communicate with Google servers, the end of support will directly impact how your OBi device can be used with your Gmail account and its associated Google Voice phone number. Unfortunately, you will no longer be able to use the Google Voice communication service to make calls using the phone connected to your OBi device. Also, the ability to receive calls to your Google Voice number, directly from Google’s service, will not be possible.