Quoted from Jappie:
What a magic line up for Bally from this year. I'm a fan and lucky enough to own 2 machines from the list; a Fireball II and a Flash Gordon.
Flash Gordon is one of the best classic pins ever. But even the Fireball II, probably the least popular of Bally's class of 1981, is very fun and extremely beautiful. It's Dave Christensen's final piece of art in pinball.
If Centaur II counts as a Class of '81, I now have the privilege of owning three machines out of this amazing streak in pinball. Fireball II and Flash Gordon are the others. I like all three of them, but the nod goes to Centaur.
I've owned an Elektra a few years ago, which I enjoyed a lot for its uniqueness. It did get a bit stale after a while. I really enjoy Embryon, but find it a bit lacking in the rules department. And I'd really like to have some more hours on Eight Ball Deluxe, Medusa and Fathom to know if I like them better than Centaur.