I use only RHPs and CHEs in my cages. I don't use UTH as I personally don't trust them. Sure with a good T-stat they are fine but if the T-stat goes fritz, then you can have a cooked snake. With a T-stat fritz on a RHP or CHE, the snake will probably be warm but he/she can move to the cool side and doesn't run any chance of being burned. That being said, I've never had an issue with only ambient heat.