The install is fairly easy for the most part. It installs like WP does, but ofcourse you have to have domain aliasing set up just like with BS. Also the htaccess can get you if you aren't careful.
After that it's like WP 2.0, but you have the main site interface built into the main blog dashboard.
Some -plugins can be placed in the MUPlugins folder and will instantly activate for each blog, but you have to play around with it to determine which they are.
As far as a VPS install, I don't know if there are any particular concerns because I've never tried VPS hosting.
If you are comfortable with WP you should do fine, most people who are afraid of trying MU out are just not that comfortable with most software anyways, which I think is not your case.
One special note that was a gotcha for me for over a week... your xmlrpc has to be addressed as
http://blog.domain.com/wp-inst/xmlrpc.php though you would insist it should work without calling the wp-inst folder, you have to for it to work. Of course you have to have this right to use BAP with it.
