G. Barnes,
Two issues:
First, I recommend that you install some means to lock your torque converter before you install an exhaust brake. My old '95 truck blew the transmission lines off their (plastic) fittings twice due to fluid temperature. It was less than a year after that before the transmission needed a rebuild.
Second, I have owned a US Gear exhaust brake since about 1996. I have had a few issues regarding reliability with it, but I think I now finally know how to keep it working.
The solenoid has never given me any trouble, even down in the mud and heat. The first problem I had was a failure of the pull-coil relay. It was an inexpensive part, but difficult to figure out. The brake would cycle on and off when it was engaged. The pull-coil relay had stuck closed, and the self-resetting circuit breaker was cycling.
A couple of years ago, I required a new controller (outside of warranty). This was an expensive part, and US Gear did not offer to give me a break on the price. In this case the exhaust brake was not closing properly when engaged. It's possible that this may have been related to sticky bushings (see next paragraph. )
The more recent problems have been mechanical, primarily with sticky bushings at the butterfly valve. I suggest taking the butterfly valve out when the unit is new so you will know how to do it. It's a 15 minute job, even if you've never done it before.
I recently had to take mine apart to clean and polish the bushing surfaces and to apply some anti-seize on the moving parts. The brake now works better than when it was new.
US Gear's technical help is first-rate. During working hours, you will get a real person fairly quickly, and he will know what he is talking about. Their service for parts is also great. Prices are sometimes a bit high, but the parts are shipped right away.
All in all, I'd buy another one, knowing what I know now about them. If you get one, keep those bushings lubed.
Loren