Just. Unbelievably. Great. Engineering.
The blade withdrawal system isn't a big surprise - Saw Stop's approach, although well engineered, is obviously a bit of a design kludge. I really like the PCS approach (which of course also gets to take advantage of 20 years of advancement in electromagnetic actuators and solid state switching). Anyone who thought seriously about it concluded a long time ago that non-destructive withdrawal and braking systems were possible and preferable, if you could get around Saw Stop's patents.
But wiring a saw blade to both generate a sufficiently consistent field around itself, and to detect the back effect on the control circuits from a body part several millimeters from the blade is just outstanding, and at least to me, a bit unexpected. I'm really impressed.
Unfortunately for me, a kappa 550 with PCS would cost more than my entire tool inventory, but my, I do want one.