they are pretty stiff, but they make stiffer. If you want to soften them up real fast, stand one up on a carpet. and flex it repeatedly. I did that with both skis for like 5 minutes a peice and they softened up real nice. If you leave them stiff, and don't take a file and totally annihilate the edge underfoot like I did, then they rip all mountain as well. They worked just fine for me on rails, even before i destroyed the edge completely. In pow they were still fat enough to keep my skiiny ass on top of the pow.
Depending on your groomer to pow ratio, I think that either these or the seth viciouses would be the best one ski quiver you could get.