Sync ratings bidirectional between iOS and iTunes on PC? Is it possible to synchronize library meta-data, specifically the star ratings, bidirectionally between iTunes on PC and iPad?

I am rarely listening to music, but if I do so, it is likely on the iPad (mini) hence ratings will happen sometimes there but sometimes also on PC. In order to make that worthwhile however a synchronization from iPad to PC and PC to iPad is necessary. 

So far I have only found threads were adventurous workarounds and many posts said, that synchronizing even ends up removing ratings from their mobile device. Is there really no possibility to get (preferably automatic) bidirectional synchronization of this data?

Another possibility mentioned was iTunes match, but since I don't use music too often, the annual fee seems too high.

PS: I strongly prefer non-jailbreak solutions.
You can turn off manual mode and use automatic syncing -- this will maintain the ratings both ways. In iTunes you want to be sure "manually manage music and videos" is not checked. 

Might need some tweaking if you don't sync your whole library though.  Best way I found to solve that complexity issue is using smart playlists...