Macbook pro 2006, Coreduo 2.16, 2G RAM, installed SL on Tiger 10.4.11 very smoothly, the auto-installer is great, 45 minutes, and my desk is exactly as I left it...Absolutely no problem ! Everthing seems to go faster. NO ISSUE AT ALL... I've got 6Go extra free space after installation (54go after, 48Go before) Well, so far it's a great OS... I use mainly my mac for Music : Logic Pro 8 run successfully, only some few audiounits don't go through the validation, but no major recent release. Logic 8 runs smoothly : I load a song which use a lot of CPU and use to stop regularly, here with SL it goes till the end without any stop due to CPU load... Reason 4 is running fine also. Deckadance also. Safari 4 is pretty fast.