It probably isn't better if you are only looking at the gaming perspective. It very easily holds its own, and the difference lies in the size. All of those notebooks you mentioned are 17" behemoths, while this is a mainstream 15.4" screen. The chassis itself is smaller and made of carbon fiber, which is always a plus. It has a slot load DVD Super-Multi-Ultra whatever whatever. Gets better battery life on a mobile 64-bit processor (more than 2 hours on DVD and 2.5 or 3 on light use), and it helps with a little bit of future-proofing by having the true 64-bit capabilities. It's cool factor rivals that of the Alienware, and at 2100 dollars it is quite a steal compared to the XPSGen2 (w/o coupon) and 7700. Sager can get pretty cheap, and I think there is still a 500 dollar off dealy floating around.
So long as you want great gaming performance with regards to mainstream notebooks, you've found your weapon of choice. It has the x700 which is the best in smaller notebooks (sub 7 pounds). It is 1.3 inches thick or so and weighs in at 6.2 lbs or so, which is comparable to the mainstream Asus Z71V.