Badmouth,
I assume you mean by "no nag" that there are no nasty little pop ups that annoy you or ask you to push your joystick left then right? I'm running MAME32 and if you could offer another more stable MAME build I would appreciate it. I'm using 32 because it seems to work with the "games" I have.
It only asks you to push the joystick left and right for "ok" the first time a game is launched.
It won't ask again after that. But if a game is unemulated or has issues, you'll still get a pop-up telling you as much.
I have them disabled on my cab, but keep them on my laptop where I do troubleshooting.
Sorry if I come across as harsh, but this is something newer people should know.
I'm not a dev, but I know it annoys the piss out of them to see people asking how to correct issues when they put a big red box on the screen to tell you it has issues and there's nothing that can be done by you presently to fix it (unless you can code to improve the emulator).
If you're using a no-nag version and a game doesn't work, it's good manners to check it on a standard build before posting about it.
plain vanilla naggy builds:
If you need the UI:
MAMEUI
http://www.mameui.info/Official MAME:
http://www.mamedev.org/