I always appreciate power and torque. Cummins is the king of the hill up or down! Especially the ISX engines.
When running those engines I have rarely ever had to use the air brakes while using the Jake. Great compression and engine size = better exhaust braking. Size does matter! Larger displacement diesel engines don't work as hard either, and many times yielding better fuel economy.
Something to know, is stab breaking! Saves brake linings and lives.