I've been using Skeddly for several months now to automatically backup the EBS volumes attached to my EC2 instances.
I'm really happy with it so far. I liked the way I could define which instances to backup: only instances with a specific tag are backed up. I just have to add this tag to the instances I want to back up. No need to do any change in Skeddly each time I add an instance. I had to define 2 actions in Skeddly: one to backup the instances and one to delete the old snapshots.
And I receive emails to inform me the actions (backup and expiration) have been successful or not.