Smartphones are great for books, but you need an OLED screen (and hence no backlight). I was a very early adopter of eInk tech - got into it when Chinese started making the first affordable alternatives to the very first Kindle. It was great, but eventually, the smartphone won out of sheer convenience - it's always there in the pocket with me, so whenever I have to wait on the go, I can just whip it out and continue reading.