Quoted from Rum-Z:

Neo, the poll is asking which one you would sell. According to the poll, the majority of people seem to be indicating that they'd sell GNR and keep AFM.
I respect everyone's opinion on GNR, and GNR is a fine game, but there's something about AFM that I love. I know I shouldn't love AFM so much because it suffers from what someone once called "B.E.P." (Big Empty Playfield), and yeah... I know Williams/Bally's goal was to produce the thing on the cheap, so there's not much to it other than a UFO mounted on a spring and 4 jiggly martians (that look like they could have came out of a department store gumball machine) mounted on coils, 3 ramps, and 2 flippers. But I find the game incredibly fun. That big empty playfield makes for some great multiball action in my opinion, and the rules are accessible and easy to understand, and any time I step up to it I feel that I have a chance to rule the universe. Of course, if you get bored by achieving the wizard mode of the pin once (in this case "Rule The Universe"), and then you find the luster has worn off the machine as you've conquered it, well then AFM is probably not for you. Luckily for me, I haven't got bored after repeated rulings of the universe, and I feel the machine continuously challenges me to beat my grand champion score, and some day I'd like to rule the universe twice in one game. Maybe after that, some of the luster will wear off the game for me, but it hasn't happened yet.