Alienware has a solid reputation, but I don't know if that's changed since Dell bought them out. Honestly, I haven't looked at laptops much in the past few years.
From personal experience, I'd steer clear of any computers from Dell. I had three different top-tier models of Dell laptops that got progressively worse in terms of problems requiring factory servicing and/or replacement. Combined with their hidden discounts and the fallout of outsourcing tech support, I'll never look at a Dell computer again. Not worth the effort to cut through the bull poo.
The Macbook Pro isn't a gaming lappy. Gaming has never been on Apple's agenda, and you would be better off running games on Windows IMO. Since big publishers like EA (who have publicly committed to the Mac platform) are just porting their Windows titles through crappy Cider, I don't even think of playing games on my Mac Pro anymore. I've tried two Cider-ported titles, and neither was stable.
It doesn't sound like you're going to be doing anything that couldn't be done comparably on a PC. Unless you're planning on film school, I'd look into Alienware first.
