The Nook Tablet has the exact same screen but updates Android from 1.3 to 2.3 (Gingerbread). (mashable.com)
This is the exact same screen that the popular Sony Digital Paper employs. (goodereader.com)
The Paperwhite has the exact same screen as the Nook so it's not going to be any different, although Kindle's fonts are better and more optimized for larger sizes. (blog.the-ebook-reader.com)