If a 1911 is built to specs, it will run. Perhaps if more manufactures built them to specs you would hear less about problems. I only have experience with 4 1911's new in the box, 3 were Colts, 1 was Springfield, I was lucky enough that all were built to specs, they all worked out of the box. Made the Springfield better by tweaking it and putting in some parts I wanted instead of theirs, but it still functioned with their parts. Had a friend who picked up a 1911 cheap because the guy said he could not get a full mag through the pistol. We took it apart and cleaned it and oiled it, thing was dry as a bone and dirty, set aside the stk magazine and used a couple of mine, put in all new springs. We could not get it to fail, it was a good deal for my friend and also inspired us to look for more "good deals".
I don't believe in the 500 rds break in, I buy one of these all I will do is mess with the magazine, maybe the recoil spring, check extractor tension...after that if it would not run perfect I would send it back if it were me. Let the factory put their 500 rds through it, I'm saving my ammo for when it actually works. It would be nice if no manufacturer would put a defensive pistol out the door that did not run, but as already mentioned, they turn them out fast and not all get looked at close enough. The 1911 I carry will shoot no matter how you hold it, limp wrist, tight, doesn't matter, it just shoots. Probably hear about more of them that don't work than do work, if you stop and think about it, it's still the most manufactured pistol out there, everyone makes a 1911, including custom ones. Custom ones are nice because they can build them tighter, but they make sure everything works with tight specs too, that is why they are custom.
If they rattle a little I don't mind too much, long as the barrel locks up in the slide nice when it's in battery, it will shoot well. I don't know how the 1911 got such a bad rap on reliablity with all the 1911's out there used in competition, but I suspect some of the problems people have could be easily fixed for not much money. I do think the people who use 1911's are very committed to knowing how they work and the proper maint. on them, if your not one of those you might get very frustrated if your having failures when all it might be is a magazine problem or extractor problem. Might be something worse too...it happens sometimes.
Jim