Well everyone who keeps snakes in a rack system uses belly heat (UTH or flexwatt). If you live in a dry climate, lamps are your worst enemy. I think belly heat is also more beneficial for digestion.

Does this mean heat lamps shouldn't be used? of course not. People use them without problems all the time. I just think a UTH would be a better investment.

I will make a chart since I have no life!

UTHs

Pros:
Easy to use
Widely available
Helps aid in digestion (this is more of an opinion though)
Doesn't take up a bunch of space
Doesn't zap humidity

Cons:
Kind of expensive (unless you get flexwatt!)
Need a thermostat (which is expensive)
Sometimes isn't enough to heat the whole cage in cold houses


Lamps

Pros:
Inexpensive
Widely Available
Variety of wattage available

Cons:
Zap humidity
Need a thermostat (expensive)
Sometimes doesn't heat inside hides
Can be stressful to a nocturnal animal
Bulbs burn out and need to be replaced often
Night temp drop (if you turn them off)

This is from my point of view and I am biased