C3500 '93 or '04 axle?

[1ton-o-fun]

I'll never understand why folks with heavy duty drum brakes fantasize about disc brakes.

Reading about people having trouble finding ROUND brake drums from any parts place doesn't make me feel warm and fuzzy. No, nothing is currently wrong with my brakes, but knowing that I will have trouble when the time comes isn't cool.
Just weighing my options.