Jungledisk workgroup is a smaller package, but for a lot less money. Also, storage fees are per gb, which is nice. We use it for our 4 person team and pay about $20 a month. Same encryption and shared storage features.
5 users over the course of the year on Jungle Disk: $240 320Gb of storage on Jungledisk for a year: $576. Total
I'm tempted to say these are non-competing products since you can just mount the cloud disk with Jungle Disk, but you need to sync with Dropbox, but you can do the same with Jungle Disk.