With Amazon's Cloud Drive, I can store:
1. Anything I buy from Amazon for free forever
2. Anything I upload into my Amazon Cloud Drive, including, apparently my Apple iTunes-purchased music.
3. I can play anything from my Amazon Cloud Drive on any device and on as many (PC, Mac, or Android--for now) devices as I like, either by using the Amazon Cloud Player on the device's browser OR by downloading the MP3 file to that device and its native player
I DO have to pay for storage for anything I didn't purchase from Amazon--but it's $1 per Gig per year (after my first 5 gigabytes for free). Oh, and I get 20 additional Gigs free if I buy 1 song from Amazon.
And I can always export/download everything and store it locally if I prefer or don't want to keep paying Amazon.
Biggest surprise to me was the fact that I can apparently export all my iTunes-managed music to the Amazon cloud. Big slap in the face to Apple! I suspect that most people will keep both--itunes and Amazon Cloud, but migrate anything they want to play ANYWHERE to the Amazon cloud.
Oh, and by promoting music storage and "play anywhere" capabilities, Amazon is subtly promoting its cost-effective Amazon Cloud storage for personal storage of ALL my files -- including photos and videos and documents.
What's not to like?? What am I missing??