I've tried all 3. About 5 years ago I made the switch to Firefox (though not on Lion). One frustration for me with Firefox is the slow startup, it's always been like that. Damn frustrating for the odd time you just wanna open your MacBook, quickly google something, and then put it back to sleep. Functionality wise, once running, it's hard to fault.
I used Safari when I first got my MacBook 2 years ago, and again when I got my MBA a few weeks back. Don't like it. The interface is less intuitive, it seems least reliable of all web browsers I've tried (in terms of crashes and some site compatibility issues) and I don't like the lack of integrated search functionality to the http bar. I also find tabbed browsing less intuitive.
And then comes Chrome. I never thought I'd enjoy a web browser more than Firefox but Chrome is easily the fastest web browser I've used, the most intiutive and functional browser for quick or prolonged use. It also handles flash better than both Safari and Firefox, which is exceptionally important on OSX.
So yeah, Chrome IMO is easily the best web browser, at least for typical everyday usage.