Looks good and responds fast to surfer clicks. The shotcuts such as Apple-T are still there, so the surfer experience is familiar… with a few graphical differences such as the tabs are now in the header of the page – thereby saving a whole line of screen real-estate.
The Top Sites is a great first graphical list of the most popular sites in your history (no page-load) and the search feature is cool how it goes into “Cover Flow” mode.
Safari 4 beta doesn’t handle DHTML to well yet. WordPress 2.7.1 locked up the page when trying to add a url using DHTML…. so maybe it’s not time to upgrade yet.