Least favorite game to play is the machine that needs a flipper kit cause the flippers are weak.
I am not a fan of any machine that is sooo very slow that you can launch a ball, go n make three coffees before the ball rolls back down to the flippers, hence most pre Dmd games except a very select few will ever get past my front doors, but that's just personal choice.
Many people have more experience than me when it comes to older games so I am always open to new ideas, but fast action and Dmd style games rarely make me pick any specific title as being very bad. They are all fun compared to not playing pinball.