I enquired about all my music etc on iTunes and according to the girl in the shop I spoke to, she said there's an app called 'easy phone sync' which is simple to use and tranfers all your iTunes data onto the new storgae provider.
I did exactly that when I moved from my I phone 3gs to the galaxy s3. used iTunes a lot so the music part was important to me. got all my music on to the s3 easy enough plus with Google music I still find it easy to buy music on the go.