My experience with air brakes have been excellent. Provided the air system is maintained properly, air dryer, tanks checked and drained as needed to remove water. The stopping power is phenomenal. When used with the two stage engine brake the DX3 supplied... well it dont get any better than that.
Now what I've heard about disc brakes on heavy chassis. When I was having transmission service done on my bus back a few years ago, the shop had a 40' class A with brakes and rotors destroyed. At the time it appeared that the brake service area "pads" and rotors weren't enough to stop this 40' monster. The mechanic says they run across these all the time. Frankly, he was surprised they even put that system on such a heavy coach.
Unless they have made drastic changes in the system similar to Newell Coach, I believe the flimsy systems being installed out there wont be as reliable. They have their place, but maybe not in the big chassis market... but again, maybe big changes have been made that I'm not aware of? For me, I'll keep my air drum brakes..
I do know for a fact that Newell Coach uses disc brakes with ABS but unless builders are going to use these massive systems, the rest wont work.. some engineers get it !
Slim, RVing 30 plus years
2015 Dynamax DX3 37 RB