In TFB's announcement about ETS Clear MP5 mags (New ETS Mags And Loader | SHOT 2017 - The Firearm BlogThe Firearm Blog), they state the following:

"[ETS] worked at solving the issues with the MKE Polymer magazines. They found that the loose tolerances of the mag and mag well fit would cause rapid wear of the plastic mag catch notch in the side of the magazine. So they beefed up the polymer to fit better and take out as much play as possible."

I purchased a few of these MKE mags from @gm (who has great mag prices) but have not fired them. They seem like they are well made. I haven't even inserted mine but was contemplating getting more. Can anyone comment on the allegation by TFB that these mags experience rapid wear of the catch?

Please do NOT turn this into a thread about the ETS mags. That already exits here: