It took a lot of time to get my hands on Mac OS X Snow Leopard and when I finally managed to do it, I get one of the greatest frustrations in my life.
First of all, it’s full of bugs. Looks like Apple was in a rush to release it and forgot to iron out some rough edges. Problems go from stupid connectivity problems using AirPort to more serious mad Guest account deleting everything it shouldn’t.
Second, there’s the speed. At first, it looks faster. But when you start opening your apps, let’s say, about 10 of them, things start to get flaky. The system makes a lot of disk swapping, meaning this thing is more memory-hungry than its predecessor. People with 4GB or more of RAM aren’t complaining, so that might be it.
On the good side, Preview is actually a useful PDF reader now – you can properly highlight things on a 2-column layout document, Exposé and Dock (particularly the Stack) are better and Finder support 512×512 pixels icons (imagine a gigantic .mov icon playing video – yeah, that’s possible).
Overall, Mac OS X Snow Leopard still needs some polishing. If you haven’t upgraded, I advise you to wait a bit until the most annoying issues go away.