The MP3's I have listened carefully to - my own music - when compared with original WAV file sound like crap: very thin, very narrow, very AM radio.

Also, I have to get the documentation: the liner notes, credits, art work is sometimes as or more important to me than the music itself, which seems orphaned and lost in the world without names and facts to anchor it. If I hear something I like, I want mental mileposts to help find it on the map or it just drifts off into the Great Uncharted.

Any service is going to have to take this into account to draw my attention, time or money.