Until I got a Kindle Voyage, I found the Kindle reading experience to be subpar to books (but still more convenient in most cases). But with the higher resolution of the Voyage (300ppi), better backlight, and most importantly, buttons to move forward/back instead of swiping, I now prefer the Voyage over paper books.

Much easier to read one-handed on the train, and having a good backlight makes for convenient reading at night (with the screen brightness turned down enough that it doesn't bother my partner). I've pretty much stopped buying paper books now, while with my old kindle, I'd alternate between paper and digital books.