The artwork on Flip Flop seems to be somewhere between Bally Amigo and Gottlieb Mustang. I have yet to venture very far into Bally EM. I have a Bally Eight Ball 1977 and my friend owns a Xenon. I love those early Bally SS.
What are some other Bally EM favorites? I'll have to keep my eyes peeled on craigslist.