Custom Alienwares are much better.
But if you're a rich kid or you work for the CIA or you're a professional graphics designer, i recommend those insanely expensive custom ASUS, CyberPower, Coridium, Acer, etc.. Why? The best PCs aren't actually from the biggest brands in the world (Alienware, Razer, etc.), because those brands only make expensive PCs. Companies like Acer makes crap computers as well as extremely great ones - companies like that are usually better. It's a bit hard to explain. (like how Logitech headsets usually beat Razer - not saying that Logitech is a small company, i know it isn't, but noobs know Razer much better)
It's like Apple all over again. Only the inexperienced people in mobiles choose iPhones over Samsung cuz they look fancy and more high tech (SAMSUNG IS BETTER BY SO MUCH)
I've started a nerd war, haven't I. No hard feelings.