Condition, pitch level, side-to-side balance and strength on the flippers have some saying on the feel of pinball machines. Tough or fair.
I have neven played Pinbot. But the Jackbot I have access to is probably the highest level of bitch slapping, I have felt. There is just something unexplainable about the buttom geometries that demands outlane parties. Damn. And the saucers release the ball differently each time.
On top of this I have trouble with the ramp. But it might be caused by a lazy right flipper.