belly heat vs back heat

If properly controlled I see little to no difference.

I have both. Im my vision rack I have belly heat, but my handmade rack has back heat. I actually prefer the back heat it seems to keep the snakes warmer IMO.

i use both. from what i gather large tubs have issues with back heat and also does cold rooms.
but back heat is cheaper to run and tends to keep a more even heat. it also tends to be warmer on the ambient temp side.
this also depends on how nicely the tubs fit in the rack.

Back heat all the way! I dislike belly heat because of problems ive had with it in the past. Just not worth it to me :)

Belly heat. When i used a glass cage i used both to keep the air temps up in the 80s

belly heat, loved by snakes.

Both, but more back. I have a four cage sliding glass setup, it has lights that heat from above but it also heats the bottom of each cage. I hope this makes sense. My next cage is going to be a Jason's Jungle rack.
http://www.jasons-jungle.com/racks.html

I don't use racks, but I use both in my RBI cages. Belly heat to create a warm spot, and back heat to keep the ambient in the right range.

I use belly heat. The ambient air temps in the tubs can have small differences with just back heat. The belly heat provides more of a temperature range. For example the room temp is 75 the tub ambient air temp is 75 cool side 80 warm side with a belly heat of 90. If you use back heat the snake will not be able to access a larger thermal gradient. Also, for cooler rooms I prefer belly heat.

I guess this depends on what you are looking for. Temperature stability or larger thermal gradient. I prefer the latter for my applications.

I have one rack and it came with back heat. I think that belly heat would probably be better for cold climates because you wouldn't have to keep the ambient room temperature as high.