I have had an Invisibrake in my Jeep Wrangler for a year. Before that I have the Roadmaster air actuated cylinder in my tow car. The Invisibrake is easier. However, it applies the brake to my tow car when the engine brake goes on. The previous one did not. Also, a month after having the Invisibrake installed it died. They put in a new one. A computer glitch.
Between the Roadmaster Invisibrake and the Roadmaster air cylinder I am 6 of one, half dozen of the other. Might have to flip a coin to decide. I have no idea on the Redibrake.