$50 difference:
http://www.amazon.com/dp/B004DI7ISM/
http://search.barnesandnoble.com/Ant...9780132117326/
$40
http://www.amazon.com/dp/B004A7YQRM/
http://search.barnesandnoble.com/Tru...9780132655729/
I think if your primary source of books is purchasing them from the maker of your ebook reader amazon might be better here. But if you have epub source (b&n, sony, kobo, library) and care about sideloading and not being locked down to source, then amazon doesnt stand a chance in comparison. Ability to loan used to be a plus for nook too.