Take this for what its worth...
I have a medical animation business running high end 3D software, editing and compositing programs. My render farm is made up of 6 PC's running Windows 7, networking flawlessly. I can upgrade components anytime the latest and the greatest comes out.
If you buy a Mac, it will be pretty to look at and easy to use. It's not overclock or upgrade friendly, and costs more.
Depends on what you need it for, I guess.
__________________
|