They can be finicky, but if repaired properly, they can be quite reliable. They do require service more frequently to keep the music roll pivots oiled since they slide and well as turn. They need to be oiled with a slightly thicker oil such as keystone medium weight spring oil. The index plate with the spiral groove also needs a drop of the same oil. They are definitely a pain to work on since these movements have a lower tolerance for wear and sometimes it’s tough to find all of the wear points. Bushings must be perfectly at the original center as any misalignment of wheels and pinions will rob essential power from the train.
