The Andersons do get scuffed from stones but so what. I've been using them for over a year now and haven't experienced any cracking, chipping or breakage. I did have a problem with them sliding once on wet grass.
Who knows why there are negative comments on Amazon about them. I think you could look for gold on Amazon and someone would give it a negative review. I sometimes think folks post comments/reviews on Amazon just to get published and get a little attention. I've never talked with anyone who has had them break or crack.
I have seen lot's of broken Lynx levelers in CG dumpsters.
