Welcome to the forum! WOW, what a jump!!! Once upon a time I had a 3GS.
What exactly are you missing?
I have heard DoubleTwist recommended a lot when wanting to come from iTunes to Google.
One thing to keep in mind is Apple is closed, they are behind, and they don't want to make it easy to change. Worst case scenario, you might have to rebuild some playlists, movie collections, etc. The good thing is with Google you can access your content from any browser and almost any device, so if you set everything up again, you will have much easier access to it in the future.