BuddyPress.org

You should absolutely wait till 1.2.. Most important factor is the completely rewritten Activty stream which adds SO much to the overall experience for your users. It’s the main reason why I’m “stlll” waiting to start working on the final design of my site!

Andy also mentioned that 1.2 will have backwards compatibility built in and 1.1 plugins should not break. At the moment they are not working because those functions are not yet in the trunk!