Correct me if I’m wrong, but I think this is the first time in computer history that any company took time to optimize a core product, like operating system, for performance, size, stability, and not include more user features.

Apple decided this time to focus more on application developers then users. To make Leopard a better platform for application development. Is this new release only about developers then? No, end-users will benefit not only form more hard disk space, speed or improved stability of the new operating system. They will, in the end, also enjoy wide range of improved applications that are going to be built on top of new, underlying technologies not visible to them at first.

I wish more companies would follow and take time optimizing they products rather then rushing new features in.

Said that, there is no rush in upgrading your Mac. At least from end-user point of view. Snow Leopard has very few improvements in terms of user experience. You are just fine with good, old Leopard and all you favorite applications running on top of it. Wait till all the compatibility issues with your favorite applications are ironed out and upgrade then. Unless you want to have the latest and greatest OS running on your machine as soon as it is available and are willing to accept that some of your applications will not work right from the start.

Update: Read the ultimate Snow Leopard review by John Siracusa at Ars Technika.