How funny I ran into this thread while building an Alienware M17x myself and sought the answer to this EXACT same question. Before I begin ranting, if you were choosing between the AMD and nVIDIA chip, which would you pick and why? I've had so many problems with the nVIDIA I'm leaning towards the Radeon, but I'm not sure.
That said, I'm so sick of all the Alienware bashing. Do you really think that people buying Alienware computers think they're paying the same price as someone independently building their own computers? Well, maybe some do, but any intelligent person does know. Let me explain why we still choose to buy them:
1. We don't know how to build a computer, nor do we want to.
2. We have the money to spend. It isn't an issue. We either saved up for it, or we're wealthy/spoiled.
3. Brand loyalty. I bought my first Area 51 Desktop in mid 2004. Aside from a single internal dvd /cd drive breaking two or three years in, I used it without any issues until 2009, and it remains usable to this very day.
4. Prestige. Look in any pc magazine when they do their annual "Best Gaming Notebook of This Year" award review. Alienware seems to always win. They have a reputation for being the best. People know it. That logo you posted is the same thing as the LV on a $10,000 Louis Vitton purse. Are you going to tell your wife/girlfriend she's a complete idiot for wanting a pair of Dolce & Gabbana sunglasses that cost $400 when she could get the same quality of glasses for $20 at a mall kiosk? I hope you won't.
Many of us come here for answers to technical questions that you, pro2a, and you, MoM, can answer. So please, don't answer the question as if you guys were my father