Some worry about the failure of the Schwartz, IMO failure is as rare as the accidental discharge it is designed to prevent.
The Series 80 safety on the Colt can easily be improperly assembled so that the pistol cannot be fired. I forget whether it is the frame half or the slide half, but I think that it is the frame. Whenever the slide or frame has been detail disassembled, the pistol should be checked after assembly by dropping a pencil, eraser first, into the barrel of a cocked, unloaded gun which is pointed skyward. When the trigger is pulled, the pencil should fly out of the gun.