For me, GI issue or Pmags.
There are some lemon 30 GIs out there from the ban years, but not so many.
A mag is essentially disposable, so if it fails you, mark it and put it aside or toss it. Most of them work just fine.
I've tossed a dozen mags or so in the past 20 years that just didn't work, and only felt bad about it during the AW Ban years. Otherwise it's just taking out the trash.
I've got hundreds of mags these days - for AR types mostly GI 30s with green followers, and some with the newer tan followers. Also about 20 vietnam-era straight 20rd mags mostly OK or UI, and some Colt, that work just fine and fill out an ammo can reasonably well when you're storing loaded mags away in a 50-cal ammo can.
I have some C-Mags, and they work, but are inconvenient to store or carry or even transport, IMO.