I'm running an iMac 1.83 ghz, MacOS 10.4.11, 1.5 gig ram, ATI X1600 w/128 MB ram. I always run CoH in windowed mode.
Ironically, of the options of WinXP in boot camp, any MacOS solution, and Cedega on Linux.. I've gotten the best performance from Cedega, with basically full functionality. It works quite well, but.. you know. Linux just doesn't compare to MacOS X yet for usability, as far as I'm concerned. It's got a long ways to go.
The MacOS options at present are Crossover/Crossover Games, and a virtualization environment. I've never been able to get mainline Wine working in MacOS, so I don't include that.
The game runs more or less correctly under Parallels, but at a significant performance reduction. It's usable, but sluggish. I wouldn't go on a TF or timed mission with it. I haven't tested VMWare Fusion with CoH; I don't currently have that product.
Crossover isn't yet even remotely at a comparable point to Boot Camp, Cedgea, or virtualization. It doesn't support the various shaders that CoH uses, so you get a very 'flat' visual experience. The overall performance despite that is decent, but not as good as native, or through Cedega on Linux on the same hardware.
As far as I'm concerned, Crossover is currently unusuable due to input issues, both keyboard and mouse. More specifically, there are problems with it 'eating' input when you use anything that opens the input line. Enter, backspace to reply to a tell, a slash, etc. It also doesn't 'release' the input line focus after you hit enter, you have to hit escape twice. Additionally, mouse behavior is erratic; if you're using the mouse to turn or rotate camera, and the mouse hits the edge of the window, you get rather chaotic mouse movement. It also is less stable than other solutions.
These issues apply to both Crossover and Crossover Games.
... all that said, I consider Crossover a worthwhile product. I've used it for other games, and for actual productivity. (i.e. doing my job) I've purchased it and already extended my support license once, and I've pledged to purchase two copies of Crossover for my friends once CoH reaches a usable state.
And, happily, last I checked Crossover Pro for Mac also gets Crossover Games as a compliment.