On my list of things to do are:

1. Get download to write out ID3 tags according to the empeg database.
2. Support arbitrary filename formatting for the download (e.g. you can specify {artist}\{album}\{tracknr} - {title}.mp3 and stuff like that.
3. Remind Mike to add the clone "swap" button (or do it myself).

As far as the playlist hierarchy goes, this is fairly simple. What to do if the track appears in multiple playlists, though?

Alternatively, I could download the whole lot and then generate some M3U files (can you nest them?).