Personally I really like buddypress, I am using it on a new personal interest website actually based around wordpress.

Its still early days yet however, I have found it to be very flexible and easy to use, hopefully my community site will grow.

The reason I chose buddypress, is I want a site that has a real community experience, rather than a blog with a few entries (which I will still have) but I want people to interact, create groups, post useful links, make friends/network, share tips and more.

I believe that buddypress has a way to go, but it really is off to a good start and credit to Andy Peatling and his team for creating something a little bit different.