I'm using Arq since 2011 to backup my most important data to Amazon S3+Glacier and can highly recommend it.
Today v4 has been released and comes with new storage options (GreenQloud, DreamObjects, Google Cloud Storage, SFTP aka your own server), multiple backup targets, unified budget across S3 and S3/Glacier, Email notifications and many more clever features.
Today v4 has been released and comes with new storage options (GreenQloud, DreamObjects, Google Cloud Storage, SFTP aka your own server), multiple backup targets, unified budget across S3 and S3/Glacier, Email notifications and many more clever features.