I use the Sansair device - it seems pretty solid and is very easy to use. I'm not sure how much I'd trust a hack I would do that involves water and electricity, but others who work with hardware more I think would have no problem. The device is incredibly dumb, it's really just a circulator, heating element, and a decent voltage regulator with a thermometer and some basic logic gates to raise or lower the voltage when the temperature is closer or further away from the target.