Well, the E-Readers have gone through a lot of variants but the recent ones that are out in the market are the best for your reading experience.
The latest "eInk Carta" screen type was introduced in 2015 with a better and higher contrast display for the best reading experience. It's exactly like reading an actual paperback, even under the sunlight.
But the best is yet to come.
http://123helpme.com/ebook-readers-o....asp?id=158705
I read this paper published back in 2008 that predicts the future (i.e. now) and what an ideal ebook reader should be like. I see that we are there already with the predictions coming right.