I use them. and have for a long time in numberous s/w and SiG pistols.
Technically Mec Gar is probably a little better than oem... They build mags for SiG, berretta, and numberous other high end manufacturers to stick their name on and call "factory"..
They are the best "aftermarket" around.
I see no reason why man should not be as cruel as mother nature.