The Mac does use an accelleration curve when moving the mouse pointer. So if you want to move the pointer all the way across the screen, move it quickly; if you're doing some precise graphics editing, use a slow and steady hand.
Windows uses a linear correlation, so if you move a PC mouse one inch it will move some distance x; if you move it two inches, it'll move 2x on the screen no matter how quickly or slowly you do it.
Being used to the Mac, I find a PC mouse to be intollerably skittish. If I'm trying to hit a small target, I have to hold my hand absolutely still and approach very slowly, and hope I don't sneeze. If an ant sighs, I'll miss and have to go back and try again. The Mac mouse is so much more precise.
I'm sure you get used to the way the two systems work after a while.