I have the built-in controller in my 2011 and love it. It knows exactly what the truck is doing and applies the trailer brakes as need. Now, I do have the exhaust brake also, so the Duramax does a lot of the braking saving wear and tear on both the Truck brakes and Trailer brakes.
2011 Chevy Silverado 3500HD LT Ext Cab 4x4 Duramax/Allison, 2016 Redwood 39MB, Disc Brakes, Mor/ryde IS, GY 17.5" H tires, 5.5K Onan, Dual ACs, auto level, auto sat dish, stacked washer/dryer, residential fridge, King sleep number. Michelle & Ann