I'm a Firefox user on Apple, and I find it buggy and it crashes frequently on my favourite sites. One of these is Typepad.com. I'm forced to use Firefox because Safari doesn't work properly with Typepad.
I switched to Mac for personal use a few months ago, and the whole experience has been a huge disappointment for me. I sigh with relief when I sit down to IE6 on a PC running XP. Obviously my mileage varies from yours...