I recently ditched Safari in favour of Fx for about two months. In the end I got fed up with the crashing/speed/functionality/lack-of-nativeness, so went back to Safari, which I have to keep closing every so often as there seems to be a memory leak somewhere (on Intel) which caused it to slow down like a wench >_<
I also tried Camino, but couldn't handle the lack of features, and I still can't get to grips with Opera as a day-to-day browser.
Safari is still the daddy-o of Mac browsing, however there definitely seems to be some issues with the Intel build, as I can use it for days on end without a single shut-down on PPC.