I've been testing a beta product called the Encrypted File Storage System (or EFSS) in a production environment for a while as an offsite backup solution. I'm only backing up 200MB of compressed data, but it works very well. Most backup solutions rely on pushing or pulling the data across a network. EFSS puts data to be backed up into an emulated file system locally and transparently encrypts and compresses the data. Each 4KB block of data has a timestamp associated with it, which makes incrementals over a network blazing fast - faster than anything else I've used.
Yesterday I was monkeying around on my server and removed a few installed packages that I didn't need any more. Unfortunately, removing those packages caused a critical configuration file to become corrupted. I then fired up the EFSS command-line shell and mounted everything except the last 24 hours of incrementals and exported the configuration out to the file system. I did an eyeball diff, checked a few things on the file system, and restored the configuration back to what it had been. If I didn't have an EFSS-based backup (e.g. had been using rsync), I would have had to rebuild the configuration from scratch and that could have taken several days instead of a few minutes.
You know your backup solution is working when you can rapidly recover from a data loss. EFSS also recently helped me to move a functional website from one server to another with permissions, owners, groups, and timestamps completely intact in a fraction of the time it would have taken me using other backup systems.