And I don't use it. Sure, every once in a while when I don't have any work to do I'll boot into OS X to see if I wouldn't be able to use it for just a day or two, but I always end up booting back into 9 after a half an hour or so. I really do like OS X. Honestly. I have tried many times to use it as my sole operating system, but each time gave in and booted back into 9. I am a Mac user, we are supposed to be the most productive computer users in the world.
Time is one of the biggest factors in productivity.
Navigating through the finder or an application in pop-up windows is very slow, especially when navigating through something with a large amount of items, like your Mac OS 9 system folder. Applications startup fairly quickly, but not anywhere close to the startup time required in Mac OS 9. There are no more Hot Keys. I save an extraordinary amount of time using my F-Keys, the only reason I ever open my hard disk from my desktop is to perform file management of some kind. Switching between applications is slow in OS X. Minimizing windows spikes the CPU Monitor, and takes longer than it should just to get something out of your way.