BuddyPress.org

Chaps I think the OP does actually make reference to understanding the essential difference between WP & WPMU

The question asked is whether there is some OTHER reason one is better over another apart from multiple user blogs, and I believe the answer to this question is no! BP runs just as happily on standard WP as it does on WPMU with the only real difference being no user created blogs just Groups and group forums and the one master site blog?

Andy is best placed to answer this though.