My previous diesel (1994 Dodge Ram 3500 CTD dually) had the Jacobs RamBrake installed. It was great when towing the fifth wheel at a GCW of 21,180 lbs. over the Continental Divide, the Cascades, and the Sierras. It was even nice when just driving around town, or when hauling 35 bales of hay.
My current truck does not have an exhaust brake. I miss it. But, I don't miss it enough to spend the $1000 or more to have one installed!
However, if we were to get rid of the motorhome and get a toyhauler (not likely), that would change