the non turbo 7.3 IDI's are damn near unkillable, but they're gutless as fuck. Turbo ones aren't far behind either. They are one of those engines that will run on literally anything that burns and isn't gasoline with no/little modification.
LBZ's are pretty good, but the trucks they're attached to are terrible, bad frame rust because of shit design, trannies are okay I guess, they don't sound very good (imo) and that generation of chevy is just plain ugly in my eyes. Good middle of the road power stock, easy to work on, parts are usually a little hard to get ahold of, but I've always had luck finding quality ones.
5.9 12/24v is like the jack of all trades, good at everything, doesn't excel in one specific scenario, modular as hell, lots of headroom for upgrades and can make boatloads of power if you pour enough money into them. The trucks they come in are called "shipping crates" for a reason, their transmissions fucking SUCK, and their bodies rust out like sin.
7.3 powerstroke: good engine, kinda another jack of all trades, looses points for HEUI injection, just a good reliable engine.