I know it doesn't mean much but I literally cant stress how much I want you to take my word for it.
I even thought that same thing myself: 'what are the odds that I'd get one of the few shitty ones.' All in all I think there is a reason you see more bad reviews and dissatisfied customers on Cyberpower reviews than other prebuilts.
As far as building your own PC. I literally knew nothing on how to do it, but took about a week to really study and watch lots of videos. Ordered most of the parts from newegg and had a successful boot my first try =) It was stressful and I was up until four AM finishing it but I'm glad i took the extra effort to do it.