A mac is a damn nice machine, but its not easily upgradable as a PC, its design is damn nice if you like that kind of look, tho the standard mouse that comes with a mac has been proven to hurt your wrist. Also they are pretty hard to stack on top of eachother.

The power of mac is nice, but as Kevin said you can buy 3 PC's for the price of one mac and hereby getting much more power.

Maya uses OpenGL and is very stable on PC, proven through the past many years. Mac has just recently gotten it. You do the math,.

Good luck..