If you are satisfied with the way that Apple and iOS manages your songs and such, then switching to Android will require a change. I have managed to organise my music collection in my own way. With my Android phone, I found that I can manage my music multiple ways and chose the way I am most comfortable with. It is not difficult to get MP3's into iTunes. I think going the other way is not very simple as I understand it. Switching environments is going to be some hassle no matter which you switch to and from.
In any case, thanks for posting your experience and thoughts on moving from iPhone to the SGS3. It's unfortunate that it did not work out for you.