I hate to repeat others...... but here goes. I have ordered from CDNN several times. No problems, quick shipping, good prices.
I have tried USA magazines before. All of the ones I personally have tried were crap. Some who have replied here have had better luck.
I might be tempted to try a couple for $10 each, but would limit the use to range time, and save the better mags for carry. There is something to be said for having a mag or two in your practice rotation that malfunctions from time to time, in order to practice F2F and other drills.
I have taken old 1911 mags and altered the feed lips to force failures, and my training partner and I slip them into each others rotations for a little surprise from time to time. A skill that too many overlook IMO. Just be sure to have a fool proof system to identify these mags, and store all practice mags away from carry mags.
BT