I just worked though most of the new features applicable to me in the new beta. My overall impression: a real winner with some questions.
-Potentially my favorite feature - Quick select. This is the selection tool that we should have had for awhile but didn't have the horsepower to enable it. It's really intuitive. I say potentially however, as I found it to be a little gratuitous at times where I almost have the whole area I want selected and it proceeds to select it all. I assume I need to spend more time with it and/or Adobe does :)
-Auto-align has a lot of potential that I am still thinking about. I could see a whole lot of potential in having this ability in AE 8 :)
-Speed. Not even a question. It's fast. Start up time alone is fractional to CS2 under Rosetta. The UI is more responsive and the brush lag is gone.
-Bridge: Not working for me. It simply won't load so, I can't comment there until I figure out why.
That is my initial impression. I am really hopeful that it will get even tighter.