I mainly play Bombjack, just played it with sound and it ran 100%, the sound sounded a bit weird and crackly but that could be because my Asus ROM isnt the latest one.
Tried PacMan plus and the only sound i had was the theme tune when i started, again sounded a bit unclear. Arkanoid the music was again a bit unclear but the sound effects hitting the bricks etc was alright.
I must admit i dont always put the sound on on these Mame games. The ones i tried run 100% but like i say the sounds a bit off but that could be because i dont have the latest rom (Cant be bothered to get the latest one as i dont want to wipe out whats on my PPC)
The amount of potential games you can get if you get an Asus (Eg GBA, Genesis, SNES, PC Engine, Mame) etc is just incredible