The ease of sending large documents, as well as being able to send them from my phone (iOS). I like that it's easy enough so anyone who has an email address could be using this service without having any prior knowledge about how things work with computers/email etc! It would also help if they had more options in terms what you're allowed access too once your account becomes active - right now there isn't much flexibility beyond just uploading something into their system which will then become available through some kind of web interface later down when someone logs onto our website / sends us emails asking where we've uploaded stuff before? This makes sense but maybe give people other ways than logging out & back again after every upload?!