The only value with a Google Voice number is that it was free and I could call in and out with it. If I have to jump through hoops to use it, it no longer has any value. To me there is no value in having a Google Voice number that is just used to forward to another number. You get a call in; you are not home, and they leave a message to call them back. However, to call them back you have to use another number they don't know. You may as well give them the real working number instead of the worthless Google Voice number.
I think Google realised that Google Voice without a real working in and out sip solution was fairly worthless; many may sign up for GV but not use it. That is why they partnered with someone that already had the hardware and the arrangement is probably that Google is getting revenue from the arrangement. Polycomm or whoever it was, probably complained that people were able to use free open source solution and not buy their overpriced hardware so Google came in with their heavy hand to crush us.
I say continue to use Google Voice if you can, I know that the gurus aren't walking away, they have the knowledge to continue. It is us poor saps that don't have the knowledge that have to throw our hands up in the air. Like I said, if Google wants to take my number, take it Google and shove it where the sun don't shine. There are plenty of VoIP providers that are not the evil bastards that Google is with their track all Chinese users so they can be reported to the Chinese Gestapo.