IMHO...MC PSI sensed without an accelerometer is not as good as a P2/3
When my P3 is turned on by the brake pedal switch...it goes to whatever preset I've dialed in
Then the accelerometer takes it from there, while those only sensing MC PSI, will only provide the preset amount.
You'd have to press harder to get more trailer braking
I can stop the whole thing without getting into MC PSI. If course slow going...like at a camp ground
Dislike having another hydraulic tap into my braking system, but that us just me...