I'm pretty sure all those options require a subscription, no?
EDIT: I'm not sure now -- I might experiment a bit with this to see if it'll save my notebooks from the device to other clouds. It looks like you can use it as a quick way to get PDFs to your device, but if you use it as a journal you are SOL.
I don't think you need a subscription, however you need to upload the files to their cloud and from there it is uploaded to other providers. You cannot sync directly to your services. IIUC.
Their subscription is just required if you want to store files for a longer period of time.
