I tend to agree with Byron about the Jordan and its pedal-position approach. In addition, the changes in pedal height with engine vacuum (assuming the power-assisted brakes
that everyone has in this century) are as large as the motions of normal brake activation, so I am not at all convinced that the pedal position is a good indication of the desired braking effort.
Having said that, there is one advantage to responding to driver action (pedal position or pressure) rather than acceleration: descending a hill at steady speed, these systems will apply the trailer brakes
, even though an acceleration-based system might see no acceleration to trigger brake application.
I would be happier with brake system hydraulic pressure, like the Ford system, but Jordan users certainly do report satisfaction with the product.