I’ve used them so I can add my take. I was aware of Knee Bindings over 2 years ago, but like many have said their looks were somewhat uncompelling. Then in Spring 2011 I bought them when they offered a red and black carbon-fiber version. So after skiing park in them for about a year I can give my thoughts:
I only ski park hitting 20-30 foot jumps most of the time, occasionally something bigger. While learning 3’s I frequently crashed and landed backseat. Many were spinning rear-weighted falls with the left leg splayed out. Not sure how many were classic Phantom Foot falls, but spinning crashes would seem to be a fertile environment. So with the kind of encouragement one would expect from the 14-year-olds on the chair lift, I eventually turned my 200-lb crashes into recognizable 360s. Some thoughts:
1) There were no ACL tears; lots of bruises, though.
2) Occasionally I switched out my Knee Binding skis (173cm Dynastar Distorters) for my old 161cm Salomon 720s with S912 bindings. Back came an old left knee pain between patella and shin that I’d forgotten about while using the Knee Bindings. Perhaps the elastic release was mitigating whatever torsional force was occurring while popping switch, landing spins, etc. In any event the Salomons transferred this pain to my knee where the Knee Bindings didn’t.
3) There’s definitely more control with the Knee Bindings. Where previously I could carve a sloppy turn with the Salomon’s, now I would drive in an edge with the same maneuver. A more subtle pressure would provoke a greater response. This forced me to clean up the turns.
4) I don’t know if the lateral release – the one that saves your ACL – ever engaged. I do know the skis flew off many times and I never injured my knee. Unfortunately there’s no way to tell if the lateral release was the reason for the ejection. It’d be cool if a plastic tab popped out to announce one had occurred (or better yet in my case, a counter.)
5) It takes more effort to get the boots in. I don’t know if this is a thing with just Full Tilts or all boots, but gearing up in the old S912’s is much easier.
Included a pic of my setup: