So it sounds like a dropbox-like service running on NAS with the added wrinkle that they provide a way to automatically sync your userland folders to the dropbox.

I can see the appeal. There's a lot of room for innovation in good UI for NAS. Having a plug-in server that Just Works (after you install the client onto your devices) seems like a good product.

I wouldn't be surprised if they run a skin on OwnCloud or something like it for web-access to your files.