Brew Belt, Pad or Aquarium Thermostat?

In your humble opinion which method do you find works better at maintaing your temperature? I myself have a 2 zone fermentation chamber; one side doubles as my kegerator so I keep that side around 38 F and the opposing side stays between 50-55. I know at some point, im going to need to hit temps above 38 but below 50 on the kegerator side and temps higher then 55 on the other side. Just doing some advanced research.

I use an old fridge with a carboy heating pad tywrapped across the back. With a two stage controller, I can dial in any temp I want. The fridge cools and the heat pad is more than enough to keep the inside warm.