I have used mine for about 2 years as well, and they have been reliable for me. They do have about a 5 degree swing, so keep that in mind, and make sure your tank is set up and the temp. where you want it before you put any snakes in. You can use them for more than one heat pad, but you need to plug an extension cord with multiple outlets into it first (UTH wattage is so low you don't really have to worry about overloading the ESU). Put the probe into one tank and just monitor your temps. You probably would want to keep snakes of one type on one thermostat--for instance, I have my rosy boas on one and my king and corn on another, because the rosies like it a little warmer. The ESU isn't as exact as a Helix, but if you can't afford the Helix, the ESU works just fine.
Jeannie