It would seem most malfunctions here can be attributed to ammo either being loaded too light, too heavy or poorly.
Mechanical failures seem to be dominated by broken springs, poor maintenance or infrequent cleaning. Other parts that are not springs do break, but not as frequently. Also, bad QC on a few factory fresh guns.
All in all, it's not bad for a mechanical device that controls explosions.
Springs are always the weak point in any mechanical system. I just had to replace a $2 spring that broke inside the transmission on my Harley. That $2 spring cost me $800 to replace. Most all of that labor of course.