I may sound crazy but
I have OS X on a partition, as others do. But whilst it is fast and stable (although I have had two horrendous unix text over the screen crashes) I'm sorry but I find the look too intrusive. 9 is smart, doesn't crash much anymore, and discrete. It has stylish clean icons, not these hideously outdated, photo-realistic, HUGE, icons. Aqua is smooth and crisp I grant you, but it looks over-produced. Even at it's smallest the dock is much more intrusive than the less-functional but useful control strip. The drop down menus, especially in Illustrator, take up most of the screen!
I would love there to be an OS X, with an enhanced 9.2.2 look, and all the unix gubbins in the background making it mullti-task and stable.
Maybe I need to give it more time, but at the moment, it's interface and structure slows me down and puts me right off, and I have to say, amongst many colleagues I am not alone.
Still the new G4, bottom of the range I bought yesterday rocks!