For the $75K+ this thing costs, no way I would take it before a proven truck like a Duramax.
I wouldn't say the Duramax is proven, unless you mean proven to be problematic. I have a friend who has a fleet of these and they have so many issues it's ridiculous.
Driving up to Ft. McMurray to various sites in winter / snow falling, they have to ensure they keep multiple air filters because it gets clogged with snow and freezes, putting the truck in limp mode. They've had numerous issues with DEF systems, injectors, transmissions (it ran out of fluid, but no leaks - how does that happen?), transfer cases, etc. These trucks are bone stock and relatively new.