I downloaded a few days ago and webpage loading is noticeably faster. I was a bit miffed that my Multirow Bookmarks add-on wouldn't work, but surfing the Mozilla forums offered me an alternative. Everything looks good, so far...
BTW, I also downloaded IE 9 this week. It has always amazed me how MicroSoft can produce some truly great software, but IE has always been an awful piece of crap. Instead of releasing another crappy IE, they need to come out with a new version of Windows Media Player.