We have x-chocks and I can testify that they don't remove movement 100%. A friend has them as well, and his is much more steady. The difference is our "box" seems to sit up higher than his by design, and we have spread axles where he doesn't. I think it all plays a part.
I will also say that I typically give everything a little more tightening a few hours after we get all set up because stuff changes. My only negative experience with the x-chocks was one where the ground was pretty wet and we must have sunk in after awhile. We were there for about 4 days or so, and when I went to leave, I had a real problem getting one of the x-chocks off. Typically I can loosen them to the point where I slide them out, then collapse them the rest of the way. This time I had to collapse one all the way just to get it out.
I also use them in conjunction with my regular chocks. I have the regular ones there..I might as well use them. Takes all of an extra minute or so.
