Fwiw, I now have a 2010 lmm with the factory itbc. On my previous 2 trucks I had a prodigy p3, the previous truck to those 2 had the max brake. My 5th wheel is a 2000 model so I have used several different trucks and brake controllers pulling the same 5ver.
The prodigy p3 is by far the best controller of any I have used. The factory itbc in my lmm is terrible. Braking is smooth, mostly due to the lack of braking! Even turned all the way up or even grabbing the hand bar, the itbc provides little power to the trailer brakes.
Dealer has checked it out many times and could find nothing wrong with it.
For the money, and if I did not have the itbc, I would use the p3, without hesitation.
The max brake I had on my ford was better than the itbc I have on the lmm, but still not near as good as the p3.