The STC-1000 is a dual stage controller, so it control both heating and cooling. This is awesome for a fermentation chamber, where depending on what you're fermenting and the ambient temperature you'll either need to heat or cool the fermenter to maintain your set point.
For a kegerator, you can probably just wire the cooling part. That's what I did for mine.
If you're ordering one on e-bay, you should probably just order two. Once you see how awesome it is you'll want to get a dedicated fermentation fridge.