Who should I buy from?

Alright, I’m going to buy a new PC, and the options I’ve considered are Dell, Gateway, Alienware, and then building my own. I don’t really want to deal with building my own, though I knows it’s the cheapest, but I want to know which of those would have the best customer assistance. Also, if there are any real problems with those companies like they are about to fail, which I doubt, that would be nice to know, too.