linux isnt good for anything having to do with graphics. not really anyway. while there ARE drivers written for linux, linux isnt made for that.
as far as mac goes, mac is fine for your average user, but for anyone looking for a bit more in terms of power, windows is the way to go. the mac OS itself is built to be user friendly not necessarily powerful. plus, in order to get any kine of power out of a mac, you have to spend a ton of $$$ whereas you can get yourself a powerhouse for much less if you use windows (and granted yes linux).
for example, my computer (which i built myself) is running a core 2 quad overclocked to 2.73 ghz, 4 gb of ddr2 ram, and a geforce 8800 gt video card with (at least initially) 500 gb hard drive space. that cost me $850. if you wanted that in mac? that would cost you around $3000 (now less but at the time it was $3000)