The concept is awesome...no arguments there, but it all depends on how you want to use them. There is a reason people love things like the Look pivot/Rossi FKS, Salomon Driver etc. bindings. These are not meant to pre-release if you land awkwardly. The chances of you popping out of your Knee binding while shredding park and hurting your knee is probably higher than that of using an alternative binding that is designed for such things.
That being said...if it is your knee you are worried about, you might have to alter how you ski. It might be worth checking the Knee binding out too.
All bindings are also held to the same standards. A Knee binding set at a din of 5 will release under the same amount of torque as a Look Pivot set at 5. I am sure there are more binding threads out there that explain this in more detail.
