Re: Buddypress on WordPress vs WordPress MU
WP 3.0 will have all the same sitewide features as MU. That is if in WP 3.0 you click the option to allow multiple blogs on the same install. However if you don’t turn that on, then WP 3.0 will act like a single install of WP. I think that’s what Andrea_r meant.
If you’re on WPMU and want to move to the standard WP, you should wait for WP 3.0 to make that transition. With the merging of the code bases, it should be easier.