since you know how to use encryption, every cloud storage is fine.
mega.co.nz or dropbox should work.
of course it's encrypted. but it can't hurt to use a true crypt container
The cloud may be accessible to other persons than you. There has been malicious activity with cloud services in the past.
To prevent losing your bitcoins on the cloud run several crypto algorithms and to use a very strong private key. Because if you don't, your bitcoins will be gone for sure.
Sorry, I was referring to storj. mega is encrypted to some degree. dropbox not as far as I know.
But you're correct - strong passwords are always needed. I backup my wallets in a true crypt container. ofc every wallet is protected by a strong password too