I like the setup, but it's difficult to tell how big the warm/cold areas are from those pics - the perspective doesn't allow me to see how wide the tank is.
A little more information would be great:
- what dimensions is it?
- what temperature are you keeping the sides at?
- is the water being filtered? What temperature is it?
- is the sloping earth type stuff easy to clean?

I've got a vague plan for something similar later in the year for some of our garters. I've got a 90cm ExoTerra that will be the basis of my setup, but I'm still working out exactly how I will do it.