I never heard of supplemental braking for the motorhome.
If you are referring to supplemental braking for your tow vehicle, we have a
Unified tow brake system by US Gear. It works effectively because of the system's vacuum pump that keeps the power brake booster charged. The pump goes on when touching the brake pedal and goes off after roughly 30 seconds of releasing the brake pedal.
It is installed into the tow vehicle in a "once and done" fashion.....I installed the system myself into our 2006 Jeep Liberty back in 2009. All we do is hook up the umbilical cord and the other normalities for towing and it's ready. We have had this system for 12 years now and it still works like new.
The controller for the system is mounted on the RV dash board to adjust it's sensitivity as conditions call for, while you tow.
One day we will eventually have to change tow vehicles. My plan would be to transfer the system to the new tow vehicle.
Here is the installation diagram for the system which looks challenging, but wasn't bad in reality.
Here is the controller in our 2007 E350 chassis motorhome....#2 in the diagram.
Braking force to the tow vehicle is consistent whether braking softly or braking abruptly with the motorhome. It takes some getting used to because during most braking conditions, you feel the tow vehicle slowing down the motorhome. It helps to keep the motorhome brakes cooler at the expense to the tow vehicle brakes. I consider that a "plus". Tow vehicle brakes are not worked so hard to overheat, but they do more than their share of slowing down the train, and it's brake pads and rotors are a lot cheaper to replace.
