These bindings don't work for me. According to 2 K2 dealers, my problems comes from the fact that I push around lift lines with my back foot on the toe side of the board, like a skateboard (which they claim is totally bad technique.) I've never had a toe cup before. As a result of the way I push, I hit the toe cup of the back binding occasionally. After 2 days, the toe cup was showing lots of wear. Also, while pushing, I would occasionally hit the release on the toe strap of the back binding. It took me a while to figure out that this is what was causing my toe strap to loosen up. It's really scary heading down the trail without knowing the toe strap has come undone. We've tried all of the adjustments, and nothing solves these problems.
More problems? Yep. The hinge lever can be difficult. Also, as others have mentioned, the wire occasionally comes out of it's guide. And one time, because it partially came out, one of the guides broke. Finally, when I use these with my K2 boots, I have to be real careful, because the ankle strap occasionally gets caught on a flap on the boots. Every time it happens, that flap sticks out farther and farther, making it harder to get the boot in.
I really wanted these to work for me. In the shop, they seemed like they were going to be great. K2 claims that they've never heard of these problems before. I wish I hadn't replaced my 9 year old Burton Customs!