1 Failure to import metadata (e.g. ratings) for tracks already on the device prior to the install of MMA is tracked at:
http://www.ventismedia.com/mantis/view.php?id=11552

2 Several bugs re. playlist synch and support for synchronization of playlist hierarchy are fixed in the next set of builds:
http://www.ventismedia.com/mantis/view.php?id=11564

5 M3U files are synched as a flat hierarchy (only the DB supports hierarchy). In other words, If MMA is installed to the device, then MMW updates the database via USB/WiFi sync so that MMA can 'see' the playlist hierarchy. But .m3u files are synched without hierarchy since it isn't necessarily supported by all devices, and most other apps only handle a flat playlist hierarchy.

Thanks for the feedback--please let us know how the next set of builds works for you.

-Rusty

So I finally switched to Android. Based on my use I would like the ability to sync via 3.0 USB for my initial sync. After that WiFi and USB. I started doing some tests with:

Galaxy Note 3 internal storage /sdcard
Android 4.3
MediaMonkey_4.1.0.1672.exe
MediaMonkey_1.0.4.0189 from playstore

Sync 1
I installed MMW 4.1 on a Vista Ultimate PC where one of my music backups resides and registered with my lifetime licence. Transferred over my DB (pointed DB to backup music) and set up sync to the note 3 via USB. Note 3 is using plug-in d_MWDM.dll. The only setting I changed was to erase content on device not on sync list. Did 100 songs by selecting 2 child playlists (see example below).
Opened MMA and everything was there including the 2 playlists, except for the ratings (stars empty).

Sync 2
Set up WiFi sync. Found MMW server on Note 3 and granted access on MMW. Started sync with the same setting as sync 1. The playlists are auto and regenerate 50 tracks each. This time
100 songs deleted, 100 songs downloaded (with ratings), 2 playlists deleted and 3 playlists downloaded.

My playlists are structured where I have a normal empty playlist(parent) and the auto playlists as sub playlists(child) to reduce tree size.
Example
~M iPod ->
AA-00s Rock
AA-10s Rock

1st sync USB shows 2 playlists AA-00s Rock & AA-10s Rock
2nd sync WiFi shows the ~M iPod empty playlist as a folder. When I click on ~M iPod it shows the 2 sub playlists AA-00s Rock & AA-10s Rock.

Sync 3 WiFi
Rebooted Note 3
Changed sync in MMA. Deselected existing playlists and checked the playlists listed below (10 songs on each playlist) from the MMW server.
deleted 100 songs, 20 songs downloaded, playlists 2 deleted & 2 downloaded. All is good.

~M iPod ->
AA - 4 Star NO CR/80s
AA - 4 Star Old/CR/80s

Sync 4 WiFi
deleted 20 songs, 20 songs downloaded, playlists 1 downloaded, 1 updated, 1 added. All is good.

Sync 5 USB
selected the 2 playlists AA-00s Rock & AA-10s Rock as in sync 1, the playlists did not have the parent child structure (like the WiFi syncs) and ratings were not attached to songs. 2 Songs that were played during the WiFi syncs were updated when the USB sync was done and not during the WiFi syncs.

What should the correct playlist structure be on android?

Update: since writing the above last night, I tried it on a Win 7 64 computer. MMA was uninstalled and all files were cleared. Reinstalled MMA apk, not playstore.
I did a WiFi sync 1st with 2 playlists 20 songs.
Play list structure was parent > 2 childs and ratings were there on MMA.
Then synced via USB with 2 more playlists and the sync worked with parent and 4 child playlists, all tracks and ratings worked. Re-synced a 3rd time with the same playlists and the playlist structure has the 4 childs with no parent. I synced WiFi and the playlists structure went back to parent with 4 childs.

I did a bunch more syncing and when the playlists were not parent>child using USB, a WiFi sync would fix the play list structure.

Should I send the device logs?