I've had mostly good luck with D&H, but did have some bad ones. I've had them with D&H floorplates, DSG floorplates and with PSA floorplates. All the PSA-floorplate ones and a few of the D&H-floorplate ones had issues. Just WAY too difficult to seat, almost (but not quite) like the original Elanders were if anyone remembers those. All the DSG-floorplate ones and most of the D&H-floorplate ones were fine, but I lost trust after a while and sold them to guy who loves D&H. (And yes, I told him about the issues in my guns.)
May very well be that it was just a bad batch turned out during the panic times. I can't say for sure since I didn't keep records of which mags were bought when and from where. Most people have had great luck with D&H, and most of the ones I had were fine; but there were enough problematic ones out of my D&H's that I simply lost trust, and I'm at the point now where my comfort zone is simply more important to me than my sense of adventure.
Any more, I've pretty much settled on Okay/NHMTG, Pmag, and Lancers. Have only had a couple "tight" Lancers in the 2-3 years I've been using them, have only had a couple problematic Pmags (all M3's) in the 6-8 years I've been using Pmags, and have never had a problem that wasn't due to observable, physical damage in more than 30 years of using Okay/NHMTG/Colt magazines.
But again - most people have fine results with D&H. I may have just gotten some bad rush-productions ones or something.