I am quite impressed with 2.1b1, the 'Twitter bug' loading problem in my 'My Yahoo' page seems to have been fixed (like in Firefox 4) & most of my extensions seem to be working fine. None of my themes will though. It will look for updates to some, such as Cat Thief's Sea Tab X 111. The Add-ons manager has a new look. I'm very impressed. I do miss my nerdy Star Trek LCARS theme though LOL! Has anyone else tried out 2.1b1 yet?