Also, something that I found interesting is that the DC system at Technautics is actually an AC system with it's own inverter. Apparently this is the most efficient since an AC compressor is far more efficient, reliable and cost effective than a DC compressor. In addition, if you ever find yourself needing to replace a compressor 15 years from now off the coast of Africa, you can buy one at any hardware store.
Before I bought the Technautics system, I researched the cost of all the components from Grainger Industries and found that I couldn't build one myself for much less. Since he offers a 5 yr warranty, the dicision was easy.