That's Safari 4 beta, not 4.0 beta.
Anyway, things are good here. I've had it installed since the second it came out. The new tab placement is taken from Google Chrome, really, and of course it will take some getting used to, but I think it makes a lot of sense, and I'm all for consolidation of visual space (which this provides), so I'm happy to adjust to the change. The only thing I don't like is not being able to easily rearrange my tabs anymore (having to grab them by the little corner handle is severely irritating).
Other than that, it seems a substantial improvement, I'd say. Speed has certainly improved, and the addition of full text history searching and cover flow will probably turn out to be useful when they're needed. The new pop-down searches from the URL bar and Google Suggest in the search bar are welcome additions as well. Overall, Safari 4 is a winner.
Here are some articles that are interesting:
http://swedishcampground.com/safari-...en-preferences
http://www.appleinsider.com/articles...w_leopard.html
http://smokingapples.com/software/ti...ld-you-use-it/
And an example screenshot of Safari 4 on Windows XP:
http://img.skitch.com/20090225-estaf...urb1mw9cdw.png