To my knowledge, LMP-ng does not support browsing by artist, album, etc. All it has is the "gigantic list of all songs on your card" mode. Useful when you want to shuffle all songs on your card, but not so useful otherwise.
I don't know how advanced Moonshell has gotten in terms of browsing through music files, but I'd take a look at that.
Well hang on there, I'm fairly certain that LMP-ng does support playlists in .m3u format. It's just that it would take forever to make a playlist for every artist/album/whatever you wanted, unless there's some tool out there that does it for you.