How are aftermarket ETS pistol magazines? They make pistol mags for Glock, S&W, H&K, SIG, and maybe others.
How does quality measure up to OEM?
If quality is less than OEM, are they better than ProMags?
I found the quality of ETS magazines vary. Never unacceptable, but sometimes not great.
Their magazines for Glock 42 rendered a stellar service for me. I have 6: 1 9-round and 5 12-round. Their reliability was impeccable, they take drops on concrete easily, even when loaded. They can easily be filled to capacity, stored and used that way. I have a few thousands rounds through them, which comes to about 500..800 per magazine.
But the ETS magazines for SIG P320 were disappointing (purchased in 2019). They are reliable, but they do not drop free. There's some friction, which is enough to keep them in the gun when the slide is locked back. The pressure of the follower ejects them when the action is closed, but obviously I want to reload when it's open. In addition, 1 of mine didn't activate the slide stop properly and I had it exchanged by ETS.
In addition, ETS chose to use their existing Glock 17/19/26/34 magazine body and just adapted the top a little bit to fit the P320. This means that the bottom sticks out and the plate does not match the grip's shape. Their marketing even tried to make lemonade from these lemons by proclaiming that "you can use your Glock bottom plates". Gee, thanks!
So, ETS magazines for Glock 42 are every bit as good as OEM magazines, but ETS magazines for SIG P320 are not as good as OEM ones.
As far as Promag goes, ETS for Glock 42 is better for sure. My Promags are not 100% reliable, and ETS magazines are.
P.S. Note that OEM magazines for SIG P320 are not uniform. They are made by 3 vendors: Mecgar, Checkmate (stamped with "C" in a circle), and a mysterious American company, identified as "J" in a circle. Mecgars are phenomenal, the "J" are quite good, and Checkmate are okay -- a little crude and have a higher percentage of lemons, at least when used by large departments. Some departments even go far enough to separate them and only permit Mecgar magazines when on duty. I can easily see ETS make a magazine that can compete with Checkmate, eventually. There's a room for improvement there. But they'll never exceed Mecgar magazines for P320.