I like to build computers for fun. Not as much experience as Jim, but I know what I am doing- most of the time. I would recommend to do it yourself because it is a good skill to learn. Now days it is as hard as putting together Lego. Everything marked, everything fits only one way, fool proofed with no risk. The hardest part is to apply thermal paste and CPU cooler, everything else is easy- my 12 years old knows how to build computer. And soooo much fun!
Also you probably aware that Goliath releasing new model Goliath HD available in July. Unfortunately, they do not work with Thunderbolt on Windows- see my thread on this forum. You will have to use USB 3 on HD model, which is $7000, no discounts, or USB 2 on old model $4500.