It all depends on what your goals are. The complete kit (from what I've heard) uses quality components. Although there have been some problems with some of them. You wrote one check, get one big delivery, and you pretty much ave everything you need.

OTOH, it's kinda fun shopping for parts. You get to pick every little part and component. Save money here, spend money there. And you get to come home in the evening and see what the Big Brown Truck brought you. Kinda like Christmas all year long.

Also, you can spread your costs out over a couple of years.