My experiences have been a little different than the original poster's.
American Ammo: My dealer had some of this a few years ago. I bought 100 rounds of 9mm FMJ and 100 rounds of .45 ACP FMJ to try it out since it was priced good. It ran just fine in my guns, no jams of any kind. I didn't test accuracy since I was just plinking, but I hit more often than not. I also didn't reload the brass since I wasn't a reloader at that time, so I can't comment on whether the brass is good for reloading or not. My dealer stopped selling it just a short time later because of bad reports about this ammo. Admittedly, 200 rounds is not a very big sample, so maybe I just got lucky and had a good lot, who knows. All I know is the American Ammo I tried ran just fine in my guns.
USA Mags: I had several of these for a Mini-30 back before the '94 AWB. They all ran flawlessly. I never had a problem with them. I sold the rifle with the mags to a friend, and they all ran fine for him as well. He then traded the rifle to a dealer for something else because he wanted a rifle with more accuracy than the Mini-30. Again, maybe I just got lucky and had a few good mags out of the thousands of bad ones I'm always hearing about.
Pro-Mags: I had a few Pro-Mags for a SIG P229 and a Browning Hi-Power. They all worked fine, no issues at all. I only used them as range mags, but they always worked. Lucky again perhaps?
Triple K mags: I have no experience with these. I've avoided them because of the bad reports. Maybe I should try a couple to see if my luck holds out.
Kel-Tec P32: I don't own one personally, but a friend's wife has four of them, all in different colors. She swears by them, and said she's never had a problem with them. I fired one of them and it ran perfectly. I hear far more good about these than bad. YMMV
Intratec TEC-9 and TEC-22: Again, I have never owned one personally, but a friend of mine bought one of each back before the '94 AWB. He bought them strictly for fun guns, plinkers, range toys, whatever you want to call them. They both work fine. Accuracy isn't very good, but they are reliable. If you refer to them as junk because of the inaccuracy, well that's fine, but say so, because the examples I fired aren't accurate, but they work. Besides, they weren't being marketed as target guns anyway, and they are fun to plink with.
Taurus PT-22: no experience so I can't comment. In fact I have no personal experience with any Taurus product other than handling them in the gun shop.
"Cheap guns": A friend of mine had a Davis P-380. It was the only gun he had, and the only gun he could afford at the time. I was in a similar situation, but I got a good deal on a used S&W M10 .38 revolver to use for self defense.
Anyway, that little Davis, which cost him $50 at a pawn shop, functioned perfectly with ball ammo. It would choke on hollowpoints, but ran fine with ball. It wasn't the easiest gun to shoot, sights were small, trigger pull was terrible, and the low slide would cut up our hands when it cycled, but it was fully capable of putting all its shots into a 6" circle out to about 25 feet. Not target accuracy, but it should work for self defense purposes. He bought his wife a Jennings .22 pistol for $79, and it ran great with CCI Mini-Mags and Stingers. It also wasn't very accurate, but adequate for close range defense.
We are both in better situations now, but at the time we were happy to have what we had, and it sure beat having nothing at all for defense. I was lucky I found that good deal on that used M10, but it cost me as much as what he paid for the Davis .380 and Jennings .22 combined. If I was arming two people as he was, I may have done the same thing he did and buy two cheaper guns instead of the one revolver I did buy. We didn't shoot much back then since we were always broke, but I'd say we ran about one box (50 rds) through each of our guns about every other month. Not a lot of shooting, but the little Davis and Jennings autos seemed to hold up just fine. By the time he traded the Davis in on a better gun, he had probably fired about 500 rounds through it. The interesting thing was he got $50 for it in the trade, exactly how much he paid for it. I thought that was pretty good since I thought for sure he'd get no more than $20 for it.
His wife still has the Jennings, but she no longer uses it for defense, she's the one who has the four Kel-Tec P-32's!
I have no experience with the other "cheap guns" so I can't comment on them.
Maybe I've just been lucky, but I've never actually had a "bad" gun, and I've owned more than 60 guns, never more than about a dozen at once though. All the guns I've had were all pretty good, some excellent, but none truly what I would call "bad" or "junk". Many have been sold when I needed some cash, or traded when I saw another gun I wanted more but didn't have the cash for. Many I wish I still had, but others I don't really miss just because they didn't suit me for one reason or another, or I just wasn't using them which is why they were sold or traded in the first place. Oh well.
As always......YMMV