Pretty basic - two chest freezers with digital Johnson controllers. In the winter I add a thermowell and heat wraps for preventing freeze ups in the garage. It works pretty well for me - nothing terribly fancy. I have considered looking into the core cooler that came out a couple years ago, but my fermenters are 60L Spiedels, so I don't trust the temperature differential from core to outer circumference edges within a fermenter of that size.