While I have not personally dealt with Alienware, all the research I've done while shopping for my gaming laptop has told me it's just not the way to go. Too pricy for the hardware, shoddy quality control, customer service is lacking, and just trying to put together the hardware you want is a bit of a chore.
Also, I found a website call resellerratings.com with all user reviews, meaning no bought opinions, just actual people and their experiences with these businesses. Resellerratings gives them a 2.67/10 from 1,640 reviews. Ouch.
In my research (again, for a laptop, so take this with a grain of salt) I narrowed my choices down to three: Puget Systems, Origin PC, and Maingear.
Puget has legendary build quality and customer service, but hardware choice is limited compared to the other two and it's going to run you more, overall. Mind you, hardware choice is limited because virtually every part is tested and approved to work with everything else, meaning no matter what you end up choosing, it's guaranteed to work flawlessly.
Puget also has a live chat system with highly knowledgeable experts who can answer any and every question you might have. I had no clue what "hyper-threading" was until they explained it to me. Also, I know Puget has the live chat function, because while looking at a possible build, the chat window popped up with a guy asking if I had questions, much like a real flesh-and-blood person might do if you were physically in a store.
Resellerratings.com gives them a perfect 10/10 from 1,219 reviews.
Maingear is the least expensive of the three, with loads and loads of options... that you'll have to research yourself. They have the live chat function, but I didn't use it, and there was no pop-up chat window with a guy asking me if I had questions, so take that how you may. If you want to save some money, Maingear is a great way to go without getting something shoddy. One caveat is that, according to user reviews, customer service once you get your product might not be great.
Resellerratings.com gives them an 8.6/10 from 174 reviews.
Origin PC is the company I ended up getting my laptop from. It strikes a great balance between Puget and Maingear. The build quality is superb, even if I didn't get the hand-holding I expected from Puget, the price ended up almost exactly between Maingear and Puget if I'd gotten all identical components, it was simple to determine which parts I wanted. I'm almost certain I would've been perfectly happy with a product from any of these three businesses, but I have the Origin laptop, and I can say that I'm completely satisfied.
Also, you should know that I've had this laptop for 2 years now, and for 8 months out it, I was in Afghanistan. This machine has worked far better, longer, than anything I've had my entire life.
Resllerratings.com gives Origin PC an 8.17/10 from 47 reviews.
OP, I think I managed to answer your question with the first sentence, and I hope I gave you an idea where you can go to get the product you want/need for your purposes. I think all three of these options are viable for different reasons.