I absolutely love my Vivarium thermostat, it's from Reptile Basics. Awesome thermostat for a good price with lots of bells and whistles. I got the one that can control two different racks, it has an alarm that goes off the if the heating element doesn't respond correctly. I love it and I don't know that I would get anything else.
I have a Helix (which was replaced by Vivarium), and a Rancho as well. I use my Rancho to control the space heater in the snake room and the Helix is on my incubator until I replace it with another Vivarium. I recommend any of these brands.