I have two of them and havent had any problem with either of them, and I think the last count was around 10000 rounds pretty evenly spaced through both.
Most of what Ive shot through them have been CCI Blazers, but Ive shot a good mix of others as well. The only one I had a problem with was an old box of Federal Target I had around, which was always a problem in any of my other autos as well, so I don't think it was the guns here.
I remember seeing a lot of bad press on them when they first came out, but most of that was just a couple of people who seemed to be loudly bitching, and the usual Glock haters piling on. Think Trump farting and the media getting ahold of it.
Im not saying some didn't have problems with theirs, but I don't think it was anything common or widespread, or any worse than any other makes when they first rolled out.
The only thing I might suggest, especially when they are new, is you pay attention as to how you load the mags.
This seemed to be a problem for a lot of people, and especially those who like to just pull down the assist taps and drop a bunch of rounds in. Do that, and you will likely have some troubles. Load them like a centerfire mag, and there shouldn't be any problems.
When the mags are new, the top round on some mags may seem to nose dive below the front lip of the mag, and some have said that will cause the gun to jam when you drop the slide. A quick rap of the back of the mag into the palm of your hand usually remedies that, and that seems to go away on its own after you shoot the mag a couple of times.
I have a dozen or so 44 mags, and have seen that top round nose dive a little with a couple when they were first new. My guess is, the springs didn't seat just right when assembled, and they straightened out after a couple of cycles and things settle in. I do pay attention to that last round when I load, but I rarely see that sort of thing happen. I do rap the back of the mag into the palm of my hand after loading, just like I do with any of the other mags I load. My understanding of the rear sight elevation settings is, they match the heights of the different replacement sights Glock offers.
Ive seen some complain about the factory adjustable sights, but mine seemed to be zeroed for elevation as they came (dont remember what setting that was though). I did have to adjust the windage a tad, but I do that with all my Glocks.
I put fixed, three dot night sights on mine, meant for 9mm guns, and they were pretty much right on for elevation.
I too would have liked to see them bring these out on a 17 size gun, as Im not a big fan of the 19's. Not a big deal, but I do prefer the larger 17 grip.