Does the lack of canting adversely affect the comfort of these bindings?
I guess the kingpin is sort of like a foward-back cant, but it has no lateral canting.
Also, how are weight of these things?
I don't think you will miss the canting. The IPO has a thick pad that will deform under pressure.
Regarding weight: I played with them at Buckman's (King of Prussia, PA) and they were light. If I had removed the highback, it would have been even lighter.