I've just joined this site. I noticed that in addition to the great plugin on WPMU Premium, the free-blue WPMU Dev has many open source plugins.
Here are my questions:
What do you see as the best/most useful WPMU Dev Premium Plugins?
What do you see as the best/most useful WPMU Free Plugins?
What plugins on WPMU Free do you see as being especially buggy, security risks or just not that useful?