I would still prefer to build my own rig instead of buying an Alienware or any other pre-built rig for that matter. But for me it is more of a hobby and something I really enjoy doing. Plus I can pick better components than the limited parts they offer. That just seems a little mismatched pairing a i7 six core with a GTX 760 1.5gig.
Why would someone pay for the Ivy Bridge-E when Haswell will beat it in single threaded applications for almost 1/4 the price? There are very very few programs that can take advantage of all four cores, let alone six. From AutoCAD to your favorite video game, they're all single threaded. I just don't get it unless you are one of the very few people that will use all those cores, in which case you would probably be better served with a multi processor work station build for the same price.
Ivy Bridge-E should have came out almost two years ago.
It's about giving people the options line up for their choice of parts. It provides options to consumers, whether its a good choice or not.
Alienware offers cards up to the dual 780s, GTX 690, HD 8990, ect. you can pick your build when you order an alienware. They are just offering options.