I like books, they don't need to be re-charged.
But I do 90% of my reading on my Kindle Paperwhite which I love.
I have a Kindle Voyage. It is like the Paperwhite (with e-ink) but a little better: brighter back lighting (when you want it bright), higher contrast, a little lighter and slimmer, screen flush with bezel. However it is a LOT more expensive. When I got it it had higher resolution than the Paperwhite - which was the main reason I forked out more money. Now I think they have the same resolution. So I will think twice if I ever need to replace it.
I also have a Kindle Fire

(by far the cheapest). I don't have a smart phone, so this was my first foray into hand-held devices with "apps". I read on it sometimes, but it is definitely harder on the eyes, and it is harder to organize books. I like having both Kindles.
One big benefit of e-books for me is that I definitely read MORE since I got the Kindle. This includes spiritual reading. Books are easier to buy, easier to store, less expensive, and for me, at least in some respects easier to read. (I don't know if I am not reading them as deeply)