I have two of the Hydrofarms. I like them. I also have four rheostats. I don't worry about the rheostats causing a fire. I did have one that wouldn't work properly after power outages. That's what led me to get my first t-stat.

That particular rheostat would not send power to the heat mat after a power outage. Happened twice so I got rid of it for the hydrofarm t-stat since it was my boas cage.