Echoing joelthelion, I wonder: is this just a service selling you access to Tahoe-LAFS? If so, wouldn't it make more sense to just install Tahoe yourself instead of paying them and worrying about whether their version of the code is less secure than the publicly audited version?
(Actually, even if not. Why would you pay someone to have access to your own files on your own computer?)
is this just a service selling you access to Tahoe-LAFS?
No. Tahoe-LAFS is very different (access is only over HTTP for a start)
Why would you pay someone to have access to your own files on your own computer?
Ignoring the whole free-to-use-on-your-computer-but-we'll-sell-you-cloud-backup model, there is always the old fashioned you-pay-us-for-the-software model.
(Actually, even if not. Why would you pay someone to have access to your own files on your own computer?)