I've wanted an Alienware long since before Dell acquired them. I never did get a pre-Dell Alienware machine though - sad.
However, I do have a desktop X51 R3 and while not a laptop as the OP is looking for, I can say that it is a quality machine. I've had it for like 4 years I think and it runs great.
It's a little silly, but I really don't play games anymore except exceedingly rarely. I use it as a general use PC these days and have MX Linux on it.
But I think the brand, Alienware, is still a solid buy, a little pricey, but so are Macs.