Alienware or build a pc myself

I've decided to get my own gameing pc and for awhile I thought about building myself one. But I just heard about the alienware x51 and thought it didnt look too bad. From what i've heard its pretty upgradable and i've seen videos on youtube of them running games pretty well. Although i've heard nothing but negative things about them and that building your own is better. But I dont really care about being able to run games on higher settings on a custom built one. I'd even be fine with playing games on lowest settings if it meant i got 60fps. So is the alienware x51 really that bad? 

Im getting the one for $700 btw

Build your own. Alienware is overpiced, all of it.

Build your own. Cheaper, fun, and you know EXACTLY what went into the computer.

The X51 isn't really upgradable. It's too small for most good graphics cards and those that can fit are often limited by the terrible power supply.