In line with a few posters above, I am finding Snow Leopard a marked improvement on Leopard. Loading times are generally noticeably faster, and the whole OS is much more responsive. The things that don't work for me are 3rd party apps like Safari Ad Block, Smart Scroll and such - but updates are imminent. No deal breakers though. I have to mention that this is a clean install, and I resisted any kind of migration so I could retain as virgin a system as possible, with a view to resolving any bugs that float to the surface. I did an update install first, and had a few problems that I couldn't easily solve, with the main one being safari downloading links. Instead it would open up a new blank tab, and there would be no download. This is fixed now.