I've had the Nook color tablet for years and decided to update because of lagging issues. I have LOTS of books on SD card and love the fact that I can download them right to my Nook library. Short story, I have a Kindle 7 and Nook 7 but need to know what is the best way to read books off a SD card on both these tablets. Is one, better than the other? Is it really this difficult???!!