Depends on the kind of a book. Novels, easy read - definitely better in e-form. Anything complex - textbook, or science popularization or even rich fiction - makes me miss real print. Mainly due to the lack of easy navigation. It is a lot easier to go back and re-read fragments in the real book than it is in the e-book.
TL;DR; Working with the book is easy in printed form and pain in e-format.