Don’t make too much out of how a 4th game would complement the others, eventually they will all leave and be replaced anyway. I would try to go to an arcade or show room somewhere and play the games to see what clicks. I’d be on the lookout on the market place for a good deal on a machine that interests you and snatch it vs buying NIB

Do you like Iron Maiden music?

They are pretty different but share some clear similarities. They both have center spinner loop shots that feed a third flipper. The right ramp on JP is also pretty similar difficulty wise to the right ramp on Maiden.