Side by side comparison here . . .
http://ideas.thenest.com/buying-guides/gadget-face-off/Blogs/Kindle-vs-Nook.aspx
Kindle has more legs. Nook is more open. It's an interesting tussle. I am inclined to favor B*N's Nook basically because it is more open to user choices.
I will also closely consider the new Apple iPad.
I wouldn't, but if you are specifically discussing what
you will be looking at for personal purchase, then I guess your habits are your business.
But staring at an actual regular contrast LCD screen reading books for multiple hours on end... ugh my eyes hate reading regular webpages that long.
If one is looking at an eReader, I'd say the actual screen type is quite important.
Personally, I have put off tablets and eReaders because I don't want a single function device.
The iPad, for what it is, I'll give it the credit it deserves - a functional, nice tablet. But as a multimedia device only, it just kills me. I want more functionality if I am losing a critical component for functionality - a keyboard. And carrying a keyboard around is a laughable joke.
But that is
my critique, based on what I want out of something for which I'm going to spend a fair amount of money.
Here's to hoping the Notion Ink Adam is anywhere close to what is promised. I can't deduce whether the dual-tech display uses actual eInk, or just uses a special style of high-contrast that makes text easier to read. Wonder if it's as friendly to the eyes in terms of strain.
But having the ability to use a full color screen as a regular tablet display (Android tablet to boot), and then switch the display to eReader-style with the impressive battery life that offers,
do want!.

Like I said, here's to hoping.
Tegra2 is a great SoC choice. Hopefully once that part shipment issue can be handled, Notion Ink can get that Adam out to the public. If it's around the cost for the iPad, it might be a purchase I make without hesitation (after critics weigh in, and I get hands on time).