Here's a risk that Jim Hamm describes, "Storing 'stuff' in the Cloud has its advantages, but also a real risk, too. Take a read on this article where Google just shut an individual off from his Cloud storage. He hadn't done anything wrong to violate any of Google's policies, but someone or something at Google thought he had."
(Scroll down and consider the logic of those 95 comments already posted on that site.)
"Which brings me to Gmail. For quite some time I've used Google's web-based Gmail for all my email storage. i no longer download anything to my computers or iPad -- I do everything online. What if Google suddenly shut me off from my Gmail account? All of my emails -- both read and unread -- are stored there, not on my computer. Not a pleasant thought to contemplate. I'd survive, but what a pain.
Here's Jim's conclusion, "I would never store anything of value in the Cloud. I much prefer an external hard drive for my extra storage. Could something like this happen with a Microsoft or Apple Cloud storage? I'd guess it's possible. Just something for you to think about when you use the Cloud."