Group therapy changed my life for the better.

I guess it can depend on the group, though. Mine is a general one offered through my school. It's my first experience with group therapy and I've been it for about six months now. It's just for anyone wanting to improve their relationships with people. The other people in my group are much higher functioning (in terms of jobs, relationships, social skills, etc.) than I am but they still accept me and we relate a lot to each other. (I suspect a lot of the success of group therapy depends on the mixture of personalities you get in both participants and facilitators.)
I actually found opening up to a group of peers to be easier than opening up in one-on-one therapy. That said, if you don't eventually open up you won't get anything out of it. Of course, that can be an especially challenging prospect for AvPDers.
You'd be surprised how many "normal" people struggle with feelings of inadequacy just like we do.
I take a lot more risks now and I'm a lot more accepting of myself. I'm better able to deal with my depression (the lengths between each episode are getting longer and longer, and I've had far fewer suicidal thoughts). I still suspect I have AvPD, but I'm a lot better at pushing forward in spite of it.
BTW congrats on your first post, John!