Cerakote is very durable, but it can be harder to work with as far as runs or blotches. Duracoat is very forgiving, but can be a bit frustrating if you don't have time for it to fully cure (approx 2 weeks to full cure).
Norrell's Moly Resin is somewhere in the middle. It wears pretty well, but requires a lot of prep work for the best results. The aplication is very forgiving, and teh fact that it is oven cured, means that it is ready to go after parts cool off.
As Longballer said, with any of these the prep work is the key. The best results I've had so far was applying the Norrells over a pistol that was sandblasted, then parkerized, and then sprayed and baked with the Norrells. The Parkerizing is boded to the metal, and the pores really give great adhesion to the coating. I'm sure the other finishes would benefit from the same pre-treatment, as well.