Alienware FTW!! i cannot say more for the mac as the guys above have already described it.
but if you're like me who doesn't care about technical stuff and only wanted to have fun and play. Alienware it is. with regards to the battery life. dude, it isn't alienware's fault.
technically when you have such a High Spec. (like dual video card, Hi-end processor, etc) you'd be putting up a lot of stress to the battery which in time will shorten it's life.
to fix that, I buy an extra battery. I use the default battery when there's AC power, and the Extra battery I use it only when I need portability such as when traveling.
A windows PC can do pretty much Everything A mac can do.(except if it's against some terms, but technically it can) in fact, there are softwares you CANT RUN ON MAC
like the VERY PRECIOUS HD GAMES we'd love to play.
with regards to its hardware, you should remember that Alienware is a branch of Dell - which is a trusted company when it comes to computer stuff,
sorry guys,. If you're a Mac fan, I'm an Alienware fan too. :P
and I won't argue with you, mac is great too. but not for all people., besides arguing about is like arguing about religion atheism and politics.- very very subjective.