Quoted from slochar:I always vote for free play roms, and if possible turn off the credit display as well, I've found even with free play roms if people see 00 in the credits display they don't even try to start a game.
My preference is for the credit display to show nothing *only* when credits are zero. The curious mind will press the start button. And also to have the credits reset to none at the start of a game to give players added incentive of seeing how many replays they can rack up in a single game.