If you already own a Nook device, it's well worth considering an upgrade -- the new screen and faster processor, improved Web browsing and email, and better overall interface make it a significant improvement over its predecessors.
As for how it stacks up against the Kindle HD, that's a little tougher to call. The Nook HD's screen is superior and overall the device is a much better and smoother performer; it didn't suffer from the delays and glitches I found when using the Kindle HD. Web browsing is noticeably faster as well. The Nook HD's interface is also cleaner and simpler than the Kindle HD's -- and it doesn't include ads, as does the Kindle HD. (To eliminate the ads in the Kindle HD, you can pay an additional $15 fee.)
On the other hand, the Nook HD doesn't have a camera; the Kindle Fire HD does. And the Kindle Fire HD offers a superior video library -- at least, for now. So if these are important to you -- or if you're already invested in the Amazon ecosystem -- the Fire is probably a better bet.
For me, however, the Nook HD remains my favorite. Its better software, exceptional screen, faster Web browsing and much smoother performance make it the winner in my eyes.
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