If it is for a tank (glass), an UTH is preferred. I have heard too many negatives on the plain heating pads that you by at the drugstore. For a rack system with plastic tubs, flex watt heat tape can be used. Overhead heating with bulbs is not recommended, because Leopard Geckos get heat from the belly. Hope that helps.
I had initially read the UTH had to be on the outside of the tank. I have since found a number of sites that said for glass they can be on the outside and that for wood, for ex., they have to be on the inside of the tank. Could I put a UTH inside a glass tank but under slate?
I've never used IntelliTemp. I use Ultratherm heat pads and I really like those. I think they are more reliable than the popular zoo med pads. Plus they can be removed and reused.