I don't use Boot Camp myself, but the folks I know who use it complain that the DirectX 3D stuff is gappy and stuttery and generally underpowered. Certainly that's the case on the couple of Mac-ported games I've played, so I'd be surprised if Boot Camp did better.

Probably a try-before-you-buy sort of situation, if you can find someone who does use Boot Camp on a comparable laptop.