Well 2 months in and no fix, not even an interim update. I'm one of many who must be really disappointed with the way it's been handled and without resolution. This for me is the main reason for buying the premium service.
http://community.spotify.com/t5/Mobile-Android/Playlists-keep-disappearing-unsyncing/td-p/162992
http://community.spotify.com/t5/Mobile-Android/Playlists-keep-disappearing-unsyncing/td-p/162992