I have one of the larger ones, that also has an indicator light and 4 outlets built into it. It was one of their used ones from their breeding facility. It is an on/off type, but I have never had any trouble with it. I use it for our turtle cage (I use herpstats on the snakes).
Yeah great price for an on/off if you dont care about the digital readout. It works great. I just bought a little ESU digital thermometer and taped the probes together. I have had it for about 2 years now and no problems.