Haven't used a relaxer since like 1995 but they haven't seemed to changed much in their basic ingredients/process. A lot has to do with your hair type and how your hair is going into it. I think a type like a 3b may have more success than a 4a/b. My hair is mostly 3c with some 4a. It didn't eat it up but it also I don't think took 100% b/c it did not fully relax it. Of course I was in high school, probably didn't know what I was doing and messed it up.
My theory also may not be right since a white girl I knew used one (for black hair) and girl's hair became a broom. She was a regular permer/colorer though so that could explain the damage. People though that have the looser hair types seem to fair better with relaxers of any kind from what I've seen. And, I think relaxers are all basically alike.