I have a 2007 Dodge with 5.9L CTD........first trip across USA from CA to FL truck was stock (no EB).
While in FL had an EB installed...US GEAR D-Celerator EB. Simple design: 4" butterfly valve that is opened/closed electrically via an automotive solenoid.
Has a 2" bypass butterfly to control backpressure. Push button on dash activates it.....left off on go pedal and it closes.
Truck/5vr weigh 22,000#-----EB holds combo at 45 mph on 6% downgrade.
Sure makes for a relaxing tow in mtns. and saves on brakes.
Some folks have had problems with bushing binding on butterfly shaft but I've had no issues in 6 yrs.