The official review from Engadget has made its way to the surface. Some quick quotes:

In our tests — and this may just be due to the Kindle we were using — we felt it very slightly outperformed Amazon’s option in contrast, though the Kindle has a considerably faster refresh rate when turning pages. In fact, the Nook’s refresh speed was sometimes a little annoying, with us actually having moments in between page turns of waiting for more content — not a feeling you want to encounter if you’re trying to mimic the book-reading experience.

In regards to navigation:

once you get the hang of the system it starts to make some sense, but it’s nothing we’d describe as intuitive, and your rhythm is thrown off by one major factor: the extremely sluggish response of the device. That’s right, you’re not zipping and zooming through any of these menus, you’re patiently waiting for the device to do its thing. That laggy scrolling we saw in the demo the day this was launched? Not really much better in the release version.

User Interface:

While the UI is different (not necessarily a bad thing in our eyes), there are also places where it is plain bad (necessarily a bad thing in our eyes). There’s instability to spare in the review unit we used. More than once we saw the familiar Android force close / wait message when trying to load a piece of the software up, and we encountered a lot of unexpected pauses and lag when trying to get through menus, causing a number of incorrect selections and general annoyance.

Conclusion:

when it came to day to day use, we felt let down in a big way, and can only imagine how magnified that feeling would be if we’d gone and shelled out nearly $300 for the device.

In the end, the Nook is an intriguing product launched by a powerful force in the world of booksellers, but the initial offering feels long on promises and short on delivery.

I can’t imagine that Barnes & Noble is having a very good day today. Additionally, it seems that Nooks are now not shipping until January, completely missing the holiday season – that can’t be good for them. They haven’t handled this release well, hopefully they can get it to together and give Amazon a run for their money…. then we all win

After this posted, I stumbed upon more reviews:
CNET
Gizmodo
NY Times
All Things Digital
Consumer Reports
Business Week