I've seen my fair share of 1911's come through our range and exhibit stoppages, in both LE and private citizen hands.
Some of the common factors shared are poor and/or poorly maintained magazines; less than optimal quality ammunition; guns which have been "improved" and "modified" by someone (shooter, outside smith, friend, etc); lack of good shooter maintenance; guns which left the factory with issues ... just to name some off the top of my head.
Having long been a 1911 owner and enthusiast, I remember the days in the 70's when a box-stock Colt might, or might not, reliably feed JHP's out-of-the-box, and when magazines had to be hand-selected to work with JHP's.
Now, as one of the 1911 armorers for my former agency, I saw my fair share of issues in NIB guns from a couple of the growing number of manufacturers of 1911's. Seemed as though those things might've been caught and corrected before they left the companies, but the same could be said of anything made by people.
In 2005, after I took my Colt pistol armorer class, I ordered a couple of new 1911's, a Colt XSE stainless Government and a S&W SW1911SC (stainless slide, SC aluminum frame and 5" barrel). Using a couple brands of magazines I'd come to trust, I ran an assortment of various 230gr JHP duty loads we'd used over time through both guns. Aside from the irritating instance of one side of the ambi thumb safety assembly snapping off and falling to the ground on the Colt the first range day


- which was replaced with a single side safety - both 1911's fed, fired and ejected all the JHP's I tried.
I scoped the tolerances and fit of the hammers/sears in both 1911's, just out of curiosity, and found both to have been assembled and fitted quite well. Nicely done for standard guns right out of their boxes (except for that stupid ambi safety assembly, which the Colt tech told me, when I called, was an aftermarket part they used on their XSE's at the time

).
That continued for several years, until one day one end of the plunger tube loosened on the SW1911SC. I didn't feel like fiddling with replacing it myself, because of the aluminum frame, so I let the factory replace it.
Now, several more years later, both of those 1911's are still perking right along and functioning with the same assortment of JHP's. Reliably. Since I've retired from my regualr career, and from serving as an instructor, I don't do as much shooting with them as I did when I was shooting throughout each month, but the guns still serve my needs well. I don't carry the big 5" guns as often as my smaller compact and subcompact models, preferring less weight on my hips, but those 5" 1911's have long proven their reliability, for
me, in
my hands.