Using commercial cloud providers has many advantages: cheap, efficient, allows you to work in multiple locations. Just remember that unless you have a specific service level agreement (SLA) in place, there isn't necessarily a guarantee that your data will be retrievable.
A slideshow by Skyhigh Networks points out, for instance, that even if you are using a dedicated instance of EC2 on Amazon Web Services, there's a risk your data might disappear during a compulsory reboot. The user agreement specifically states that instances can be rebooted as often as every three months, and that any data lost during a reboot is not Amazon's responsibility.
If you have replica instances and other backup elements in place, this is unlikely to be a problem (and as our first commenter points out, EC2 is primarily for execution instances, no permanent storage). However, it serves as a reminder that conditions for off-site providers need to be checked carefully, to make sure they do match your own business risk appetite.
6 Sneaky Terms That Tech Companies Force You To Agree To [Business Insider]