1. Directory structure navigation or adding to playlist. 2. Next track preload buffering 3. Software preamp adequatly built into interface to compensate for Android's insufficient number of volume steps Further not necessary but would be cool: 4. 30-band EQ 5. Bookmarks 6. Freeware or at least adware 7. Cue sheet support "Music Folder Player" and older versions of "Aimp" match them partly. Are there any other alternatives?