Like most people I think, I tend to compare reading books on my Kindle with reading them on paper in terms of convenience and related factors. But it turns out that there's a more fundamental difference between the two experiences: they affect different oarts of the brain.
You will not be surprised to learn that reading on a screen leads to the kind of skim-reading that we tend to on web pages. That and darting about all over the place (the scientific term for this is "non-linear reading").
The corollary is said to be that the "deep reading" processes we've learnt are no longer used.
This sounds like this ought to have implications for the way children learn in school, and for teachers in what kind of resources they use. Also, perhaps in employment, reading from a screen (like banking cashiers do, for example) may perhaps lead to shallower reading and therefore more errors.
On the other hand, perhaps "non-linear reading" helps people to see connections between things they might otherwise have missed.
I personally think that not enough research has been done yet to answer such questions.
For more information and further reading on the subject, please see Your paper brain and your Kindle brain aren't the same thing