I've encountered a few problems with MAMECE3 on my 3955.
Punch-Out, Super Sprint, and perhaps more, corrupt the display. Either the backlight goes higher, or the screen gets ever whiter, and all sorts of strange things happen. Exiting the game doesn't help - the device requires a soft reset.
Gauntlet crashes the game completly, the last 2 digits in the exception produced was 00000005, which slips my mind at the moment. Few other games seem to just exit gracefully with no errors at all.
Would there be a way to have a couple on screen buttons? If only to insert coins and start the game, I realize that the touchscreen drivers aren't the best, and in many cases, will slow down, but it would really help if you could just disable the buttons in gameplay.