I have the original Kindle and don't know how the Nook compares. Here are my favorite things about Kindle:
(1) download books from any location in seconds. No wires required. No wi-fi required.
(2) No backlighting is a plus to me. The e-ink is much easier on the eyes than reading from a computer screen or any backlit devise
(3) You can choose the size of the type. My senior eyes have a hard time now with some print books with tiny type.
(4) Although I have an i-Phone and read news articles on it, I wouldn't want to read a book or read for more than 10-15 minutes at a time on it. If I'm reading a real page-turner, I can read on Kindle all night without eye strain.
(5) If you get to a word of text and you are unsure of the meaning, you can look up the word on-the-spot in the Kindle dictionary, then click the back button to return to the text. I love that!
(5) You can bookmark, highlight and take notes.
(6) No matter how many different things you are reading on Kindle (books, magazines, newspapers), when you return to an item, it opens to the page you left off.
I love my Kindle. I Kindle daily.
Whatever you choose, happy reading!