frostedtim :
Constantine_99 has some valid points about the pre-built systems from CyberPowerPC, but they build and verify that the system works, and they warranty the work that they do (just make sure to read the fine print).
surely it works, it will ruin their name if their product is DoA.
i don't mind if they cheapen out a bit to gain profit but if it's some important part like the PSU (like the shady 600w i've seen) u might endanger ur whole PC with it, so i suggest whatever u choose to do (whether it's building urself / asking a custom builder) u do research first, so that when they recommend parts for u to choose, u understand what u can gain from them, what's the risk and is it worth it or not.
friendly reminder: for whatever reason, when u still under warranty, make sure after the problem happens, don't try to fix it urself and send it immediately to the company! this is crucial, if u try to tamper with it and then send it to them later on, they might consider it's a user's fault and not a faulty component, therefore voiding the warranty