By the way I plan to keep using Firefox. I miss some OS integration that Safari gives but Firefox on the whole is much more flexible and functional. And most importantly it just works without the beach balls.
I'd like to see Apple implement XUL and Mozilla do WebKit but this ain't a perfect world. Firefox it is.
By the way I would highly suggest to anyone having this issue to just move on with Firefox. I've reported this issue up to Apple many times to no avail. If you take it to a Genius bar, it's a colossal waste of time. They'll do the basic stuff you expect them to do when they put it on the bench. Hardware scans, etc. They'll hand it back to you with the problem unfixed, with some note saying they couldn't reproduce it.
Best of luck.
Same with me. When Windows friends complain about IE, I give them a link to Firefox. I use Safari and to me, seems much faster than Firefox. Firefox is only useful when you start using add ons. Only thing that Safari sort of lacks. I never get a beachball on Safari unless I load a bunch of flash sites (which happens like once or twice a year). But then again, Firefox also beach balls loading those same flash sites.