BenK
I have used a P2 and hated it!!! Yes it was properly set up and I had even re wired my brakes with equal distance cable and used stranded #10. The brakes were in good condition and properly adjusted.
I have not used the P3 so I can't comment.
My 11 Dually IBC was better than the P2 but NOT good IMHO. Installed a MaxBrake, WHAT A DIFFERENCE!!! There was NO delay, NO jerking, NO underbracing or overbearing. No joke it was as if the trailer was not there.
2015 IBC is NOT near as good as the 12-14 RAM IBC's. I will be installing my MB and using it until RAM has a flash for this BIG problem.