I use tarsnap because
- open source
- accepts bitcoins
- Colin Percival of FreeBSD runs it
- other cryptographers recommend it as crypto engineering is solid
This project Storj you use 3rd party tools like pycrypto to encrypt your own files with AES128 in CTR mode, then they just store it in chunks decentralized. I backup TB servers so will be interesting to see how they handle gigantic backups and what that will cost.
I'd take a look at our whitepaper if you haven't already (storj.io/storj.pdf)
With Storj you'll be able to choose how you encrypt your files before uploading. Remember we're still a relatively young project in rapid development so lots of things will be changing. TarSnap is definitely awesome (compared to a lot of other solutions out there), but they've also been maturing since 2006 (8 years) and had a 2-year private beta.