Well a few days into WoW on linux (Ubuntu-8 ) only, and I broke down and installed Windows XP on my machine. Here are two biggest reasons:

1. In linux, my mouse pointer is software rendered, since we are emulating a windows program in linux. This is fine and dandy when I was playing by my self, but when I grouped up with 25 other people to do Mag and Grul, I saw the challenge with the software rendering of my mouse. When we hit a lot of visual lag due to everyone casting spells, the mouse pointer would move in slow motion or I would sometimes completely lose it on the screen. I had to quickly relearn how to use hot keys. This I think was a decisive point to play WoW under windows, where even though frame rate might be low, mouse pointer would move smoothly anyways since it is hardware controlled.

2. The second piece in linux that did not work was Vent. When i was in WoW i could hear vent, but could not hit a key to speak. This i suspect could have been fixed if I did some more research.

To sum up my experience with WoW in linux, is that it has been very impressive. Besides the raid experience, soloing or grouping with a small group worked very well under linux. This may be due to the recent release of the Wine 1.0 version. About 6 months ago, wow was almost unplayable in Linux with decent graphical settings and resolution set to my native 20 inch flat panel. It is very good now, where when I solo I get almost the same performance I would get in Windows XP.

I think it is important to note that it would be great if Blizzard can release a native linux WoW client. Until then, WindowsXP for me as far as WoW. Although I will continue to mess around with Ubuntu linux and maybe find more tweaks for WoW in linux.