Have had Titan Disc Brakes for the past year. The biggest improvement having had two seals fail on the Dexter Drum Brakes is I have no worries about hidden greased drum brakes. On the rotors I can see the seals anytime I’m under the trailer.
On the brake performance, as others have noted, they stop in less distance. The easiest place I see this is when doing the Pull Test. On the drum brakes it would move some when applying trailer brakes manually, with disc, it doesn’t move an inch.
I have disc brakes on the truck and wouldn’t go back to drums, won’t on the trailer as well!