I actually just jumped ship from Dropbox to Jungle Disk a week or so ago, because I wanted the security of encrypting files/"disks" with my own encryption key. That, and I'm getting twice the space for just $3 a month.
This looks like it would be nice for a home server kind of setup, or with some disk space with a hosting provider and being able to have it setup just how you like it. I'm looking to drop Syncplicity as well, this could do the trick. Might have to give it a whirl.