In my experience if you have an Apple computer and you want to play demanding games it's better to have windows installed in a separate partition.

The performance difference for some cross platform games is huge (around 30 - 40% slower on OSX).

true, also i find the way mouse acceleration works in OSX quite annoying for games.

try this http://smoothmouse.com/

yeah i actually have that installed, but when i enable it i get issues with clicks not registering sometimes, which is even more annoying when playing a game.. Dont know if its related to my mouse or something else though.

Give SteelSeries ExactMouse tool a go.