One of the most awesome products I've seen in a while. From the user's perspective, it solves many of the practical hassles of using RAID. And furthermore, being able to boot from USB means you can build an entire new computer and not have to reinstall the OS and all your programs and settings again, which for me usually takes a whole day, plus the rest of the week to get it back to where I left off.
link to demo video
http://www.drobo.com/products_demo.aspx