It depends on the game really. I don't have a strong loyalty to either particular style of gaming. I will say that when it comes to consoles I've always been heavily on the side of Sony. But yeah, AlienWare gross. Definitely way more rewarding to build your own PC.
Ever since AlienWare was bought out by Dell, the company was ruined.
Origin PC is pretty good though, and indeed it is cheaper to build your own computer, but if your looking for someone to do it for you at a high quality, Origin is the way to go.