I have had my hands on with both Asus 750JX and Alienware 17. I bought the Asus 750JX initially but it had a manufacturing defect. I gave it for replacement but then they couldn't deliver the product within the time frame so I got my money back. I bought the Alienware 17.
At the price you are aiming, go for the Alienware or the Asus 750JX. I initially bought the ASUS as it had the 770M and 3D but I finally got frustrated with the customer service. The people in the service center were very helpful (I am talking about Nehru Place Delhi) but the stocks were just not available. After sales matters a lot at the price range you are talking about so keep that in mind. Dell also provided accidental damage cover.
The laptop usually feels bulk but after a while you can pick it up with one hand.(I am no body builder)
With a good laptop bag, its very easy to carry around (just get a good bag or tell me if you want my model). Adjust the bag properly.
The screen size makes it a problem to open in close spaces like aeroplane seats but its a problem with the screen size and not just the above modes.
And remember: the alienwareFX (lights) can make quite a lot of heads turn. you can turn them off too.