The usual first question is what are you going to use the magazines for,,,self-defense, range or competition?
For self-defense (I edc a 92) I use new factory magazines and would not hesitate to use Mec-Gar.
For range use I use military surplus magazines (Airtronic and Checkmate). I buy them really cheap and replace the magazine spring with Wolf 10% Extra Power. While I don't make it a habit to drop my magazines in the dirt or hard surfaces like concrete I see no reason to use my factory magazines.
I don't shoot IPDA but if I did I would use the already mention military surplus mags.
I am constantly on the hunt for more magazines. The good news is finding factory magazines for affordable prices is not difficult. At the moment I only have about 50 magazines three of which are no-name mags I brought during the Clinton years and they were all I could find at the time.
The no-name ones are junk that will go eventually go into the trash can (one already has). I don't feel comfortable selling them to someone else even though they work at the moment.
Most of my magazines are for 15 rounds. I guess I believe in using the magazines that are in the original capacity they were designed for.
I have some factory 17 round magazines. My Son-in-Law also owns a 92 (smart daughter) and I can't decide if it is a good thing or bad thing to give him the 17 rounds ones.
It seems my kids rely on me for ammunition and magazines.