I have a Nook, not an iPad, but I have no interest in reading a book except for on my Nook. If I had a book on my shelve that I wanted to read, I would probably just download it onto my Nook over the internet rather than read the real copy.
My Nook is the Nook Simple Touch
, which has the e-ink display. The iPad and other tablets have the backlit display. I have never had one of those, so my hesitations about them may be unfounded. Nonetheless, I am shocked how realistic the Nook screen is to real book paper, but still better in terms of being easier for me to read since it is clearer and I can adjust the font and font-size easily at any time.