yeah psp quality is good, but they tend to be volumed down than other mp3 players, and i don't usually use in-ear earphones, i think they are more tend to move rigidly the eardrums because no air was being drawn out from inside the ear, and in-ear earphones irritate my ears and so i can't hear someone talking to me, and yeah listening for a very loud music will damage the ear even you don't use earphones (eg, listening near to a taking off airplane)

and yeah walkmans do also have AVLS and i also use that, :)