The alienware one seems to be the better.
But you could also go with an ASUS or different one and get more for the price.
What are you trying to do with it?
I've heard that Alienware is the most popular choice.
Which ASUS would you be referring to? I say again I am not good at comparing and contrasting laptops/computers.
The main things I am going to be doing are playing Multiplayer/Singleplayer on Minecraft (Maxed graphics), World Of Warcraft (Maxed graphics), Blockland (Maced graphics) and Command and Conquer: Tiberium Wars (Maxed graphics). I also work with 1080p video files on Corel VideoStudio Pro.