As of the moment this chest of drawers is my favorite customized piece. (I stole the picture from Design Sprout) Customizing will always cost more then the generic products offered, but it is almost always worth it. One gets a sense of pride knowing their piece is the only one and usually it was made for that specific spot you put it in and it'll look so sharp... well this is how I feel about our computer desk and wall cabinets.
We have a weird indent where we wanted to put our computer, so to use all the space possible custom was just the way to go. My husband does wood works as a hobby, so together (I did the glueing... of course, and the standing, staining and varnishing) we made this custom piece. So to sum up, customizing will maximize all the space its designed for, look sharp and make you proud as a peach to own it.