Let’s get this said right away, the iPad doesn’t use any form of e-paper at all, what so ever. It uses an LED back lit display that contains all of the eye strain issues that has plagued monitors and laptops since the invention of the CRT. So, if you’re looking for something that gives you lots of hours of easy reading with little drain, you can count out the iPad. E-paper based devices will always win out in this area, since the whole purpose of the e-paper based screens is to reduce eye strain and improve battery life.
Si los de EpaperCentral lo dicen es por algo (lean el artículo completo donde explican porque el software de iBook también deja mucho que desear).