Price can be quite a lot cheaper OR you get a similar price but with all quality components instead of Generic RAM X, China power supply Y, Dell motherboard Z, etc. Basically you can never go wrong with building yourself unless you are needing grandma's dirt cheap email box machine. The components have become about 100x easier to put together since 14 years ago too. The way connectors are these days, it's literally impossible to plug something in where it doesn't belong. BIOS pretty much comes ready to go out of the box too (no old jumper bullshit). A monkey could do it.