Stern SS machines are under rated.
Paragon and Fathom are considered the two best Bally machines and the most commonly requested. But Stern's of the same era are just as good. Of all the games I've restored and sold, I really miss Meteor and Galaxy. I would buy another Meteor in a heartbeat - as a keeper. Another title that is under rated is Flight 2000.
Also - Bally EMs. Especially 4 players. All the EM talk has been about GTB Wedgeheads and drop target games. Four years ago, I started collecting 4 player Bally EMs, and never looked back. Bally Wizard, Old Chicago, Fireball, 4 Million BC - all great players.