I had a video chat on YM 11 a couple of weeks ago. It was my first time video chatting and audio and video looked clear and fine to me. I was going to compare it to Skype but no matter what I did it would not register or detect my net connection.
I think the main new feature in this version is the social integration. However I think YM was the last one to add it out of the big 3/4 clients (YM,WLM,AIM,Gtalk).
By the way I always uncheck all of the stuff that is packaged with any of them.