my reply copy pasted from another thread asking the same question:
"What i'm about to tell you is from my personal experience with my M17x.
DO NOT BUY OR EVEN CONSIDER IT.
During the 20 months i've owned mine i had to, replace the GPU TWICE (one of those times i had to pay $560 for it), replace BOTH fans, replace the GPU Heatsink, and replace the Keyboard.
It's way overpriced, and if you run out of warranty you're usually f***ed if something happens, the only time i'd recommend an Alienware is if you absolutely need to compromise between performance and mobility (though the mobility part is debatable), AND if you're willing to pay for an extended warranty every year (you have to subscribe for that before your original warranty expires)."