Yup.
Apple’s betas usually work better than Microsoft’s full point releases, anyway. You’ll need to have a good video card and RAM for that multi page “coverflow” web site view, I bet.
You piqued my curiosity. I just downloaded Safari 4 on a c. 2004 iBook G4; with a definitely not state-of-the-art graphics processor.
Coverflow works on this machine. At the moment, Safari is busily backfilling images of browser history (could take awhile on my minimal DSL line).