I have what I think are a Pro Mags that came with a couple of my 3rd generation Smiths. Two came with my 457, along with five factory mags. I wasn't paying that much attention to the mags and didn't realize that they weren't OEM. When I took the gun to the range the first time I got to the third magazine and the gun wouldn't fire double action. I was very concerned and after some investigation I realized that I had to mongrel magazines. Those were the Pro Mags. I held them side by side with the OEM magazines, but couldn't see a difference. I put them aside and won't use them even at the range.
I also got two Pro Mags with my 3914NL. These seem to work fine, but I've relegated them to range duty just because I don't want to risk using non OEM magazines in SD carry.
OTOH, there is another thread in this forum about someone who switched out the followers and springs of his Pro Mags for S&W followers and springs and now has 100% reliable functioning. I'm going to try that when I get back home and if it works, I'll buy OEM parts and rebuild the magazines with them.
The only magazines that people here consistently report good experience with are S&W and Mec Gar. I have some Mec Gar magazines and they are identical in every aspect to the S&W magazines except for the lack of S&W logos. If Mec Gar doesn't make them for S&W as the rumor has it, they make perfect copies.