I've been using this on windows and OSX for a few months. It uses 1/4 the memory that 2.2 uses. It's also faster and I love the new url bar. It's pretty stable outside of a few content-type errors here and there (usually on improperly configured websites/forums. Other then that it's solid, even on OSX. I'd advise anyone looking to save 500+mb of memory to check it out. Note: certain plug ins do not yet work with 3 beta 2, so if you need firebug or the web developer tool bar you might want to stick with 2.2.