The U. S. Gear exhaust brake on my 2000 truck was noticably more powerful than the factory brake on my 2008 truck. Both are six-speed manuals.
Also, the U. S. Gear unit was controlled by a push-button transmitter that you could mount almost anywhere in the cab. I had mine on the gear shift knob, and it was very handy. The button on the dash of the 2008 truck isn't nearly as convenient.
There are too many times when I want to coast in gear, but don't really want to bleed off speed, so I want the exhaust brake off. With the new system, I have to reach down to turn it off, with my old system all I had to do was push the button on the shifter, which didn't require a reach nor taking my eyes off the road.
The new brake works satisfactorily, but it isn't as good as my old U. S. Gear Decelerator, not in power nor in convenience.
Loren