overall I look at it this way we bought our herpstat pro with software. It was around 400 bucks it controls 3 racks and am waiting for another rack to fill it out. anyway it comes down to the fact its about 100 bucks a rack for thermostat. Plus you get really cool software pack that sends you a message if there is anyproblem with your rack be it to low or to high in temp. I haven't had any problems yet but if the heat went out in the house and my cages wouldn't get warm enough with 100% output i would be text at work so i would know there is a problem. seeing that my homes thermostat went out last week thankfully i was home but if i wasn't i would have found out. hopefully saving all the money i have put into my animals. I thought it was fairly cheap for a porportional thermostat. Considering everything.