A faulty bumper on a machine was as disasterous as a sluggish flipper or sling for an operator. I remember an operator collecting the coins in an arcade where there were 2 Firepowers side by side and we avoided one of them like a plague because 2 of the 4 bumpers were nearly dead. The coins in the box was about one quarter of the FP that had 4 super fast bumpers. I avoided any machine that had poor bumpers or flippers. These days there are too many other things on playfield like ramps and toys which restricts to what designers can do with bumpers.