Just installed Leopard last night. Other than losing my wireless passphrase, it was just about the most uneventful upgrade I’ve ever done. Pretty much zero interaction. Start it going, walk away for an hour and it’s done.
Haven’t had a chance to play with it yet but there are some cool features. The spinning Finder preview is very pretty and I’m looking forward to backing up my shit with the Time Machine.
On a philosophical/political side, I love the fact that there is no software protection, product registration, DRM, etc. Apple seems to be taking the lead in realizing that all that stuff does nothing to secure your software and annoys the legitimate customers by treating them like criminals. I voted with my wallet and bought Leopard even though I could have easily pirated it. I’m sure that not everyone will make that choice but I’m rewarding what I consider to be a good policy decision on their part.