To answer the question for those who don't know, yes the X Frame is the big 460 and 500 revolver. My Mountain Gun is a round butt N Frame. I'm not sure these will fit on a K or L frame.
My reason for not liking them is that they're big but still not wide enough to dampen recoil as much as I'd like. And the rubber material catches on my clothes and pulls my hair on my arm if it touches them. It's distracting and uncomfortable while walking in the woods.

These grips are black rubber.