This guy seems to work for Microsoft, and you can tell, have you looked at his blog in Mozilla? It gets a little ugly, not unreadable, but enough to make you wonder.
My opinion on browsers is: IE rocks on both OS X and Windows XP for one reason, and one reason only - it opens faster. That's it, the only reason I have. I really like Chimera (for OS X) and Mozilla, but they just take too long to open. I'm impatient. Even on Linux, Konquerer tends to open faster, so I use it more than Mozilla.