iTunes is an application with many limitations, and one of his biggest problems is being too centralized application, and provides no easy way synchronize our database of songs to other computers, keeping tabs, ratings and playlists on all of them.
Of course to solve this problem there are good applications that do the work for Apple, one of them is Sincopation, We met a long time. Another is called MediaRover and allows us sync iTunes libraries between 8 computers, Whether Mac or Windows, with support for NAS like the Sonos.
After creating our own and install the application (both steps free), not only keep synchronized music but also any changes we may make playlists or songs metadata (tags, ratings) will also be reflected in other computers. Just missing support for dynamic lists, such as Smart and Genius, and to find and remove duplicates. link
