Mame4all uses the 0.375b romsets (which is about 15 years old), and as it doesnt have to emulate newer games it often runs very well speed wise.
So its a great one to run on the non Pi2 models.
Those romsets are also pretty easy to find compared to some of the others, so it seems to encourage people to stick with it.
Not sure about your audio issue. Are you using a clean install image of RetroPie 3? Have you tried different HDMI and/or TV displays?