I had a series of games at my old office. Jack*bot did well with as a first pin, easy to understand and easy enough to get multiball, and the casino run was obtainable by many, and that had the fun aspect of 'greed' which was fun for spectators. Also held up extremely well.

Then went to a Doctor Who which the people who were becoming players liked, but was not as popular with more casual players. Currently have a roadshow there which they love, figured they were now ready for a 'mode' game and the extra flippers (I no longer work there, but they pay me to keep a machine there). They keep a white board near the machine where about three dozen people keep track of their high scores.

I found with kids, that WCS is the most popular (in some way regret selling it for that reason), shooting for the goal was obvious and rewarding for them, even if that is not really the thing to focus on.