The DC amps are noticeably cheaper than Sundown. For example, the DC PAI-2000.1 costs substantially less than the Sundown SAZ-2000d. I'm not going to quote exact prices, though. If you're interested, the prices aren't difficult to find.
I want it to be known that I'm not a Sundown hater, and by no means am I trying to start an argument here. If you prefer Sundown, that's cool. They offer nice products and Jacob has a very good reputation with the vast majority of people in the hobby. I wouldn't hesitate to run Sundown or DC products at any time...