I've been using Safari over Firefox and IE for the past week, and it feels like I'm browsing on a whole new machine. Not only does Safari have a nice, sleek look, but I love all of the little features they've thrown in. Spell check when typing, a Google search tool that doesn't take up an entirely new bar, the bookmarks bar which provides very convenient quick links, and the font smoothing thats built into the browser really gives the extra "wow" factor.
The only thing I dislike about the browser is that to open a new, blank tab, you have to press CNTRL + T.
If you want to give it a try, check it out at Apple website.