Pros: Prevents Injuries while Providing High Performance
I am an expert skier and have skied the past 19 of my 33 ski days so far this 2008/9 season on Kneebindings in NH (mostly WV). I have had NO pre-releases skiing all terrain in all conditions at normal DIN settings. I did have one bad collision on steep terrain (hit from behind) in which I was very briefly knocked unconscious, and both of my skis released properly and the brakes worked very well keeping my skis nearby. My injuries were just bumps and bruises from the physical contact, a chipped tooth, and a very slight concussion (thankfully I was wearing a helmet). After a couple minutes I skied away from this shunt, and continued skiing that day. I had NO knee injuries or bone breaks. My wife and sister-in-law are also skiing on these bindings with NO pre-releases and NO injuries, though they are not skiing at the same high level as me.
The ski I am primarily skiing with these bindings is the Head Monster iM82 (82mm waist), and the performance is excellent. I have skied lots of steeps, in fresh snow and groomed, skied bumps, piles, trees, and ripped groomers. The bindings have a slightly heel high ramp angle (23mm toe; 32mm heel) and seem very well connected to the edges, so that the skis are very responsive. This ski carves very well and handles piles of snow very well, and is a pleasure to ski late in the day on busy weekends when you are skiing back and forth between piles of pushed snow and scraped ice. I have noticed that the sweet spot on the iM82 is slightly back from normal, though my boot centers line up perfectly with the ski center. This ski also skis longer than its measurement would have you believe. I am skiing Nordica Speedmachine boots with custom orthotics.
I also have these bindings mounted on Dynastar Legend 4800 (75mm waist) and Stockli Laser SL (66mm waist), and these skis are nice as well, especially when the conditions suit them best (the Legends like soft springlike conditions best, and the Lasers prefer hard pack best). The Legend is a more relaxed cruising ski that pretty much does everything - just not at the highest level. The Laser is a slalom ski that rewards strong attention by carving deep tight arcs - but needs your attention. Both the Laser and Legend have a normal sweet spot position compared to the Monster which is slightly back of the others. The skis all perform well with the Kneebindings but I am continually surprised to find the Head Monsters do everything so well.
I have been skiing almost my whole life, and was formerly a professional instructor while attending college in New England. I still frequently get clinic'd and coached and my technique is solidly contemporary. I have one reconstructed ACL and would like to avoid repeating the grueling 6 months of rehab and spending another $20K in medical bills, so this is the genesis of my keen interest in the Kneebinding product - to which I have no relation other than being a happy customer. These are not an inexpensive binding, but they work well. If they help me to continue to ski at a high level while mitigating the risk of another ACL injury, then they will have been priceless!