it's very stable and IMHO is the vista final. there are some smaller tweeks, and a whole pile of things they need to make better, uac still sucks, there's far too much enabled by default, but it's pretty much sp3 for vista, it's better for quad cores a basic time stamp leveller for programs/ games that access the core directly, you put your ebay short cuts, clocks, gadgets and other crap where you want to, there's no side bar as such (did anyone ever use it?) as with vista the basic core is first class it just needs to be better managed. you're not going to see too much difference than beta vista sp2. vista service packs have been a collection of hotfixes and tweeks that pretty much everyone had installed from manufactures back doors, windows 7 IMHO is a service pack! they wont call it that because they can't sell it for so much.