A quick review and some brief observations:
The combined time to update both WordPress Mu installations was slightly less than 25 minutes, five of which was fixing the “home” theme on the first install because I was too distracted to remember not to over-write it, I’m just thankful I have a complete theme backup.
The general layout is very similar to a single user version of WordPress 2.7, with the exception of the newly included Admin bar by Viper007Bond at the top of the Dashboard screen. A nice touch that I expect to be easily put to good use.
To other WordPress MU managers, share a comment about your upgrading.