I looked at this site. The product, from a functionality perspective, appears to do a lot and to do it in a smart and safe way.
Two reasons I won't buy one...
1) I simply don't haul enough, or for long enough distances, to warrant the major jump in price. It's the law of diminishing returns. The controller that I have (let's call it $125) works very well and is considered a "step up" from the basic, 'timed' units. Thousands of people use this specific controller with excellent results, and don't haul enough to increase my safety margin by what can only be considered a small percentage.
2) It's ugly and big. Mounting it inside the cab will not leave a result that's eye-appealing. And, again, I don't haul that much. So, it needs to not "muck up" the cabin the rest of the time.
Adding a correction to a previous post of mine - the P3 is not a "timed" controller. It is a full proportional braking controller that applies braking force based on vehicle deceleration rate. You set the max braking force based on the load on the trailer and off you go (stop vehicle, apply trailer brake with boost lever, try to drive away - set the max brake power to where the wheels will "almost" lock on pavement). Remembers five different settings that can be tied to different trailers, or trailers with different loads.