I've been using a hydrofarm for about a year with no problems. I use it on a melamine combo rack that holds 15qt and 32qt tubs. With 11 inch heat tape used for back heat, and ambient room temps of about 75, I don't see how it could burn a snake if it failed on. The surface of the heat tape only hits about 106 - 108 f max. I'm not saying that would be good long term, but i check my animals every day, at least twice a day. before i go to work, and when i get home.
That being said I also have a johnsons that I've used for years, and you cant compare the build quality. the johnsons is built like a tank. I have a herpstat that i use for my incubator, because its proportional. It keeps my incubator between 88.5 and 88.7 .