"You should be able to sync changes without worrying about permissions or storage locations." seems to conflict a little with "We know how important privacy is, ...so no one except you and your team can ever access your files, not even us."

It seems to me that they've replaced the step of 'save it in the right location' (skydrive, sharepoint, dropbox) with 'open it with the right program'. I don't see that as a benefit at all. You even lose the normal workflow of just opening a file by double clicking it.