PRE-BUILTS, SON! I prefer them, as I don't want to go through the hassle of testing components to see if they work together; I want something that DOES work.
I mean, look at Caddicarus; his work computer broke, so he ordered parts for a new one, only for them to arrive late and not work, meaning he had to buy more components to see if they worked, which they didn't, and he lost practically a full day's worth of recorded footage during the multi-week-long PitA.
He spent over 7000 pounds on shit that didn't work - I, for one, don't want to go through the same experience.