I've never ridden on tipped rails. It looks like an obviously good idea for a long-track mountain sled in that it encourages weight transfer with that rocking-chair shape, and of course it makes turning easier on firm snow and groomed trails.
I'm wondering if there are any disadvantages for tipped rails on mountain/powder. I can't think of any obvious drawbacks. I have some vague ideas, for example it seems like a straight rail should float slightly better (in theory) than an essentially curved rail, but maybe not, maybe it's the opposite. I'm wondering what is the public opinion about this?