Yeah it's unfortunate for the last BETA. For my over a year experience with Chatter the rollback of a BETA happened only a couple of times. Usually Marc would release 'phantom' BETAs (i.e. back to back new beta updates) if there are any major problems with a BETA release. Obviously he couldn't track down the exact problem this time and he had to (sadly) rollback.
Glad that you're running fine with the stable release!
