I use them. I carry a strip of rubber from an old truck bed mat to keep them from sinking or slipping. I've been told you can pick up rubber floor mats at one of the big box hardware stores. I think you can now buy rubber mats from Anderson.
The Andersons are occasionally not high enough for the site. I carry a couple short 3/4" PVC boards that I put under the mat in that case, I've not needed more then that. Many times I just use one or both of the boards without the levelers if I only need to come up a smidgen.
Altogether I carry the 2 levelers, 2 pvc boards 8"x about 16", the rubber mat, and a pair of rubber chocks.
What I don't like about the levelers is they are narrower then the tires, if they added another inch or 2 they might also be stronger and not break, not that mine have, but then I have a small trailer.
