I would just add that internal hyperlinks don't work with the stock PDF reader on the NC for non-DRMed PDFs. I haven't bought any DRMd PDFs, so I cannot say if hyperlinks work within them, but hyperlinks don't work in the user created PDFs I've read. I tried making my own hyperlinked TOCs, but they are useless.

Bottom line is that the viewer looks good and PDFs are very legible and readable at least in landscape mode, but the viewer app has almost no functionality. I suspect a better one will come around soon after B&N opens up the apps to third-party developers.