Sorry, I should clarify my references: "vanilla" MAME = The official release by the MAMEdev team MAMEUI = Formerly known as MAME32 AdvanceMAME = Another version of MAME that was modified to improve output on TV's and arcade monitors Analog MAME+ = A version of MAME specifically modified to work with analog controls (spinners, steering wheels, track balls, light guns). Most of the code from this project has been incorporated into the "vanilla" MAME code (and thus everything else that uses it's source), so the project has essentially died off. There are countless other versions out there, but these are the main ones people around here talk about. Also, while you are not required to update your roms with each release, if a rom does get updated/redumped, it will no longer work. It is ALWAYS best to run the same version of MAME as your roms.