This probably isn't unique to Sprint, but I've discovered since switching my home phone to Google Voice as well as my Sprint phone using ObiTalk, I can no longer place calls between home and mobile. Both home and mobile share the same Google Voice telephone number.
Calls placed to the Google Voice number from home or mobile go straight to voicemail access, because Google Voice expects I want to check my voice mail, as opposed to ring my other phones.
From what I recall, I can't even solve this by adding another GV number, because you can't forward calls from one GV number to another. Are there others with this problem? Any workarounds?