So, I'm impetuous.
I went whole hog, signed up for the 2 year unlimited plan, and ported my number to Obivoice. The port went smooth except for one hiccup - it seems that due to the way I ended up at GV some information was lost in the shuffle and the initial port request was rejected. I needed to chat with Ryan and he contacted the company who owned my number and got it sorted out in minutes while I was on the chat with him.
FYI - I started with a landline, then ported it to the local cable company when we got a cable modem, then ported it to another cable modem company when we switched service, then ported it to a go-phone, then ported it to GV, then to Callcentric, and finally to Obivoice - yeah, I really wanted to keep my number.
One reason I wanted to take GV out of the loop entirely is because of the latency I experienced with it. I had incoming routed through both "dirt cheap" and "free" DIDs at Callcentric (to see if there was a difference) for CID/CNAM and had outgoing straight through GV. Every call we either made or received frustrated my wife but it was free so she dealt with it. We always had a crazy lag - like a second or two that constantly ended up causing us to talk over the other person. Pretty much every time, we ended up just hanging up and calling back on our cell phones. Your mileage may vary, and I personally know people who love GV and have no issues with it at all, but it was less than ideal for us.
I've been using Obivoice for a little over a week now, but so far, call quality is awesome, support is great, and the price is phenomenal for unlimited minutes/month. Granted, I'm not gonna tax the system, but an extra $0.08/month for the safety net of "just in case" was worth it. With Obivoice, just like Callcentric when I took GV out of the loop, there is no lag and the quality is excellent.
I'm not sure how responsive they will be to improving their service, but they have a site to add requests and there are a few there now. For example, I missed the phone-book capability of CallCentric to show CNAM. MY phone has a basic one, but it's tedious, so I added a request to Obivoice's "request a feature" page. We'll see how that goes.
I'm very pleased so far.