Just use both at the same time. Use S3 for active stuff, and Mosso as your secondary backup. The chances of S3 and Mosso crapping out at the same time are prett

Just use both at the same time. Use S3 for active stuff, and Mosso as your secondary backup. The chances of S3 and Mosso crapping out at the same time are pretty much nill. And the cost of hosting something on S3/Mosso, as a one time backup is dirt cheap