I have no problems running ANY Windows products or games on my Macs under Bootcamp and Windows XP, including GGWaW and many other Matrix products like TOAW, Advanced Tactics, Battles in Italy, BII, Korsun Pocket, you name it.I hav many other games like Fritz 9 (chess) the Total War series, combat games, Warhammer onlne, D&D online, etc, I even ran Second Life for a while.
If a product does not run, it is usually because you do not have the latest version of Direct X installed or you do not have a good graphics card. Most new games come with the latest version of Direct X.Under Bootcamp, your Mac IS a PC, so there is no reason why a Windows program would not run under Bootcamp.
My Macs include a Mac Pro, an 24" Imac and a Macbook Pro.
I have not tried Parallels, but I understand that programs under Parallels run a bit slower because they are running under the Mac OS.Older versions of parallels did not support graphics cards, but the recent version claims that it does.