The idea of building a custom home sounds great in principle, but it soon becomes apparent that you really only have a few choices when it comes time to visit the architect.
It seems that custom designs mean simply adding a few different choices to the same basic design. You might have a different kind of brick or wood, but the overall layout is pretty much the same as the neighbors next door.
With a prefab home you can actually choose exactly how you want the home to be laid out. Each module you choose is made off site and then pieced together to your exact specifications.