My father has a 2009 GMC 2500HD with the Duramax/Allison drivetrain. He recently purchased a 30' fifth wheel with a loaded gross weight in the 17,000lb range (which the truck is rated for). He has 35k on the truck.
They recently did a 2800 mile trip to Alaska and the Yukon Territories. Prior to leaving he did a bunch of maintenance on the truck which included flushing the brake fluid and checking the rotors/pads. Unsurprisingly the pads were at 85% of new all around.
En route home, they encountered a stretch of road that had multiple 10-14% downgrades with nasty switchbacks. Even with using the truck's Tow/Haul mode and engine braking, he hit a point where the front brakes were smoking profusely at the bottom of one of the downgrades and pedal feel had seriously degraded with a pronounced wobble. After pulling over to let the brakes cool, he realized that the trailer brake controler wasn't properly set and the trailer brakes hadn't been activating as much as they should. Correcting that allowed them to complete the rest of the downgrade, and the 800+ miles home, without further drama.
After that experience he wants to ensure the brakes are fully up to severe use in the future. I've recommended he upgrade the pads to whatever severe duty option is considered to be best by other owners, and ensuring he is running a high temp brake fluid.
He's curious about cryo treated rotors. The claim is that they are less resistant to warping under extreme use. However, they are $550/pair so it's not a cheap experiment.
Does anyone have insight/experience with cryo treated rotors? If yes, are they worth the $ for severe use?