They take the same input, read from the same databases, but the user experience is quite different. Any computer or mobile device will be backlit, and in my opinion this is one of the biggest differences in the type of experience you have (most people find that digital ink is easier on the eyes. I certainly do. But digital ink isn't luminous, meaning you have to have some kind of light to read it by. But by the same token, it's readable in full sunlight because it mimics the experience of reading black ink on a vanilla page like any typical book.)