Agree.
Aside from the one I pictured earlier. I've seen the ETS mags crack when dropped on the gravel of an IDPA bay.
I've not personally experienced that type of breakage with OEM Glock mags and I've not been nice to them over the years.
But I also view all mags as the expendable (disposable) and a replaceable part of the system.
Not saying I have an issue with ETS or Magpul. I just prefer OEM Glock mags.
The GLOCK mags that I bought from them in 2016 were absolute hot garbage.
I have a few 21 rd ETS mags. They suck. The smallest amount of dirt (like from dropping the mag in dirt at an outdoor USPSA match) causes them to bind up and dribble out rounds. Fine for drills at the indoor range but I'd never use in a match or serious setting. I don't see the steel insert helping either.
PMAG 21s are a little bit better but still get choked up when you're in/around sand and silt. I've also killed the feed lips on a few of them from heavy use.
I also believe that the metal feed lips may be in response to fairly common complaints about both ETS and Magpul not feeding steel case ammo.
I have a bunch of them, never had any problems since I don't shoot steel cased ammo. Wouldn't dream of using them for carry, though.
Adding nothing to the conversation since 2015....