I think many times, it is not the controllers fault, but rather the trailer wiring being too light duty, or bad connections. Having said that, I know the earlier Ram IBC had some issues, and many just changed over to aftermarket. I've used a half dozen different brake controllers, most working quite well. I have to say my Ford IBC is the best by far! My owners manual says set at 6 of 10 to start, adjust from there. At six, grabbing the manual lever at 25 mph, lock the wheels on pavement, even concrete (tires squeal). I set to 5 when lightly loaded, and 5.5 when heavy loaded. The brakes are perfect with truck, at any speed. At lower speed 30-40, I can easily stop truck/trailer, just using the slide bar of IBC only.
I think Ram has improved on their IBC, but I have no personal experience.
Jerry