The Ruby-type pistol is very intuitive to operate, even for novices. The slide stop doubles as a safety and field stripping is remarkably simple. The small size and large magazine capacity was an advantage, making it a popular "backup" weapon for troops involved in trench warfare, as well as the standard issue weapons for telephonists, stretcher bearers, machine-gun, machine-rifle, tank, and mortar crews, and rear-echelon personnel of all descriptions. The comparatively weak cartridges these pistols were chambered in gave little recoil, making them easier for novices to use effectively.
The primary disadvantage of these pistols (apart from quality control issues) is the relatively weak cartridges they were chambered in, reducing the pistol's stopping power.
The reliance on only one type of safety, and the lack of a visible hammer make these pistols very dangerous to carry "cocked and locked". Early models could come off safety when holstered in a tight-fitting holster and a large protruding stud was added to the slide in order to prevent this.
In later years, Ruby-types became notorious for the lack of standardization of parts between different manufacturers, resulting in a widespread incompatibility of spare parts that made the Ruby-types difficult to maintain. Some of this is due to the persistent confusion over exactly who made which Ruby-type pistol.