I've been using 'doubletwist' to sync. For me this is a decent solution because I'm pretty stuck with iTunes (i'd love switch to something else, but can't find a good contender that ALSO syncs with my player). So i manage my audio with iTunes and then sync to my sansadisk+ with doubletwise which draws everything out of iTunes. The only thing I have to do after syncing is to make sure that the playlists are moved to the playlist folder. Otherwise syncing preserves folder structures, which is great. It also has an RSS feature, but i haven't tried it out.
it no longer seems to be updated, however (though i can't be sure...). The group seems to be concentrating on it's Android version of the software instead. But that's my recommendation.
I think I wanted to like MediaMonkey or Musicbee, but I couldn't keep them (or whichever one) not looking beyond my music folder for music. That was very frustrating to me.