My current hosting provider, DigitalOcean, has a great backup service. It takes frequent snapshots of entire droplets and it's very easy to restore the snapshot quickly.
Unfortunately backups are only taken once every week. For our clients this is not acceptable. If you only rely solely on the DO backup service, you could potentially lose several days of work.
That's why I use BackupPC to make daily backups of all Droplets. Every night BackupPC copies all important files via SSH to a big Amazon disk. An added bonus is that, unlike restoring droplets, you can restore a single file and browse all your backups.