I run unRAID here but it's certainly not what I'd call user friendly for a non techy person and requires a bit of support, but I like tinkering. v6 has helped a lot though. It has a single redundant drive but each drive runs its own filesystem so if even two drives go down, the rest will still run independently.

I was looking at XPenology which is a Synology hack for not Synology hardware. It has some issues too though. Synology hardware looks pretty good and supports a lot of add ons and functions.

Note that Crashplan is purely a backup service. I also use it to backup my unRAID NAS and provide a local destination for machines.

Cubby.com is more like fileserver in the cloud that has some backup like functionality - looks like Dropbox. I'd still want to keep a full local copy though in case something happens to their service. You're kind of at their mercy if they're hacked or go bust.