From what I have seen so far it looks like Google wins hands down.
Google has finally taken their Google Music out of beta. I downloaded it and took a look today and have to say that I am impressed. While Apple has their iCloud that they charge for, Google’s services seems to be free so far.
I love the idea of being able to play my music anywhere I want. I have an Android phone and the app seems to work seamlessly.
If you are in the market for cloud storage for your music, I would highly recommend Google Music.