I had been holding out on installing Firefox 3 beta on any thing but a virtual machine for testing. In the past, with version 2, I had run beta's and it had been my experience that upgrading from beta to the actual releases left things a bit unstable. Perhaps the profile had changes that caused random crashes, but it was irritating enough that I stayed away. Reading crunchgear's article might just change my mind though:
Firefox 3 won’t be out of beta until the end of June but Mozilla told Reuters yesterday that anyone can go ahead and download the most recent version and run it without worrying too much. It’s now stable enough for everyone, not just developers.
And I really want to try out the new mac theme (windows/linux themes seem boring comparatively). And I don't think I can wait till the end of June!