Crashplan is cheap b/c they make it quite difficult for the average user to _actually_ backup all of their data. The interface is all sorts of confusing to non-experts, and I was embarrassed to realize I had fallen for a UI trick that made me think my drive was backing up, when in fact it was only my user directory. I'd made the same mistake on the 6 computers in the family, and had to do a bunch of phone-tech support with in-laws.

I paid for a year, so I'm using it now as additional backup, with my primary backup on a local HD and Arq.