I've tested COH on Ubuntu (linux) and it's beautiful. getting 50+ fps on my crappy single core Pent4 box with a 4+ year old AVI graphics card.
I've found two bugs. They appear in both the MacOSX and Linux versions of Crossover (when running City of Heroes/Villains):
1- COH/COV now has a new pointer when you mouse over an enemy it turns the pointer RED. Problem is, in both COH running under Crossover in MacOSX and Linux, instead of a red mouse pointer you get a grey/black giant square where the mouse should be. This is really annoying/distracting.
2- FSAA in both the Mac version and Linux version simply does not work. In the Linux version if you have FSAA enabled at all you get complete garbage on your screen when you try to turn the camera. Only way to fix it is to turn FSAA off. In the MacOSX version is just fails to work.