Should I buy the Lenovo or Alienware?

I need a laptop to last me through college and be powerful enough to handle my engineering programs whether it be 3D modeling or aeronautic simulations and such but at the same time I want it to handle my load of games (mostly Steam powered) and I need it to be exceptional performance overall. Two laptops have been recommended to me that seem to fit the needs.
The Lenovo
http://www.bestbuy.com/...Id=6339015
and the Alienware 17
http://www.dell.com/...2e7-2521cb
The Lenovo definitely seems to have the better specs and even at a lower cost, but that's what worries me. Why is the Alienware I'm looking at well above $2,000 and the Lenovo only $1299.99. Is this just more people taking advantage of a well known name and raising the price or is there something I'm missing that makes the Alienware better than the Lenovo. If you find that neither of these two are good to a laptop you know of that is also helpful.