I finally got around to installing Leopard on my MacBookPro about a week ago, and am certainly glad I have done so. I really like the “Spaces” (multiple virtual desktops) feature which help reduce monitor clutter when I’m running 20 different applications. I have not come across any progam compatibility issues and speed of launching and running applications seems about the same. I don’t know if the new features justify calling this an “upgrade” and charging for it – it feels more like an incremental update worthy of a 10.4.12 designation. I also have Leopard server, and that does have enough new features, IMHO, to justify to the cost. More on that later.
One of the undocumented fixes in Leopard was that the random switching of keyboards that we have experienced since 10.4 was released have vanished. Previously if we had two or more keyboards active, they would randomly switch whenever you moved between applications. I had reported this problem to Apple and am happy to see that they have taken care of it. The new behavior is that once you select a keyboard it remains selected until you explicitly change it, no matter what applications you are using. Mahalo Apple!