rack - heating options?

[EchoPet]

So I've been blessed with a bit of bonus cash... and I'm going to buy myself a rack. I had finally saved up enough for a hatchling rack from Nature's Spirit, and it should be arriving Thursday. When I ordered it, I wanted belly heat but Casey said he only used back heat because it was safer for hatchlings... When I get a rack for adults, I'm looking at several other brands that have the option of back heat (or specifically dual side radiant) or belly heat. Which is better? I always thought that belly heat was better for geckos, but some of these rack sites are saying that back heat is safer and more efficient. What do you use (for hatchlings and/or adults)?

 

[EchoPet]

Also, belly heat has two options, flexwatt heat tape or heat cable. And back heat can also be done with heat cable.

So which is best:
a) belly heat - heat tape
b) belly heat - heat cable
c) dual side radiant (back heat)
d) back heat - heat cable