Have been using Leopard since inception. Very unstable -- even on brand new iMac 3.06 machine. Still not convenient to simply navigate using current Finder system. Search is SUPER slow on network. Font conflicts with System Fonts such as Helvetica, Times New Roman, Optima, etc. -- no simple workarounds. 3.06 machine is actually slower than my old 1.4Ghz G4 running OS9. If Apple wants me to continue to support it by purchasing hardware that is sold at a premium, then I expect a PREMIUM product -- and that is not what this is. The reality is that Apple is designing an OS to run on limited machines that it designed -- and yet their software does NOT run correctly. And then they try to make Microsoft look foolish because they've designed an OS to run on basically most everything else out there that they were not even involved in designing. I'd say Microsoft is making MORE progress than Apple.