I am a fan of the Transporter by Connected Data. It lets you store your files on a device that you control, but you can still share files with others and access them remotely. I think of it like Dropbox without having to have your stuff on someone else’s server. I like it so much I even sell the Transporter in Canada.
You can think of the Transporter Sync as a bring-your-own-hard-drive device. You plug your existing USB drive into the Sync, and you connect the Sync to your network. You then have all of the benefits of a secure, always connected, remotely accessible device that you control, but at a lower price ($99). It uses the same software and does all the same things as the original Transporter.
Clever addition to their product line. I have a feeling it will do well.