Further to my "I have experienced significant and annoying problems but I can deal with it." vote:
My Nook Glowlight developed a hairline crack (maybe 3mm?) below the top surface of the screen. It was impossible to feel it and it was only visible with the frontlight on. The Nook was about 3 months old and had always been kept in a case.
Next time I was in the States I took it to a B&N store and they replaced it without question.