Digital books are great in many ways.
* Lightweight, I can literally carry a whole library
* Searchable, no need to take notes of where a sentence is
* Accessible, in the sense of dynamic font size
But where it fall short is the overall experience when using one.
How many time I wanted to compare two (or more) pages from either the same book or two different books?
With printed books, it's easy to leave a finger between two pages and quickly switch back and forth, and optionally annotate or highlight something.
With an eReader it's often cumbersome or slow to do so.
Being able to map a page to a list of physical buttons (I dunno, make that 3 or 4 bookmarks buttons) to quickly jump to a page would make the whole thing much more pleasant in term of user experience.