Safari here. It works well enough and it also allows me to sync bookmarks across my two computers and my phone without any additional software.
As a browser, I'd say that Chrome is slightly faster, but not enough to really be worth the hassle to switch. If I only had one system and didn't have an iPhone I would use it.
Also had some potential webpage compatibility issues with Chrome, the last being problems with an auction site's message box. Was a pain as I was using that site a hell of a lot, so went back to Safari.