Are you experienced with BuddyPress? This is another interesting question that came up during our WordPress Q & A last week.
Submitted by a WPMU reader named Kris:
We are running WordPress MU and BuddyPress as one blog setup, but the site seems to be quite slow.
Would it make it faster if we had a two separate installations? One for our WordPress blog (with all the content etc..), and another installation for users to access Buddypress. A single login would need to work across both of these sites.