Anyone else want to give out actual usage stats?
Sure.
I've got 5 CP aluminum mags (dry film, green follower) bought in 2006 that've gone through one single-day carbine class (500 rounds were slated, but it was lost brass, so I don't know) and a few IDPA provisional DMG matches. Plus whatever I've shot outside the class/competition environment. Not ZOMFGLOTS, but they've at least been used. The finish sucks, and the mags don't exactly look great from all the throwing at the ground (lefty). But they work. Function was 100%. Only malfunctions were the what we set up for clearance drills in the class.
I've also got 6 CP SS mags that I gave cursory test and called good. I used one of them in a DMG match, once. Oops. Turns out, they're garbage. The chrome-silicon springs are slack. They worked initially (by sheer happenstance) when I "tested" them, but at the last DMG match I had the bolt close on an empty chamber. Hmm. It happened again off the clock. Upon further (re: detailed) inspection one of the mags has a misshapen feed lip, another had a sloppy weld that binds the follower if more than 10 rounds are loaded. That's from the 3 that I've opened (the third mag body looks good, but has the same weak CS spring the others do). The other three are still in the plastic bag. Need to check them.
So, CP mags don't necessarily suck. But their QC sure does. For aluminum mags, there are better options at the same or cheaper prices. For SS mags, well, dunno. HK? Heh, sure. Would I buy CP mags again? Aluminum, no. SS, yes. But I'd buy in small enough quantities that I could check each individual magazine to my satisfaction.
And to my mind, that explains the love/hate fests that CP mags get on the internet. The ones that work do so as expected. (At this point, my aluminum mags are well into the bathtub failure curve, and running fine.) However, the ones that don't, well, don't.
Check your mags people, regardless of manufacturer. They're kinda important.