Firefox 2 beta 2 seems to be working pretty well now: the handling of feeds, search plugins and extensions is just how it should be, and the user interface is fairly slick (a bit too slick, perhaps). Most extensions still work, with a manual update to the MaxVersion setting in their install files, though there are still a few crucial ones that haven't been updated yet - things like Tab Mix Plus and Download Manager Tweak need a few changes to work with the new theme.