I just spent 20 minutes playing with one. The interface is just an Android app suite (library, store, search, discover) with a couple of widgets on top of Samsung's TouchWiz (for better or worse). This actually will reduce their coding effort if they simply release the same suite as the next NOOK app in the GoPS. It looked well done, and you can use as much or little of it as you want. I personally would like a more prominent library display that's simple to use on my home screen.
The reading app is nice. Nothing stellar, but pleasant to use. Font options are limited.
Move to SD card is available for supporting apps in app settings as expected.
VentureBeat has done a
hands-on article with a small gallery of pics that show some of the details.
If you want a basic tablet for reading with in-store, in-person support available, it's a nice choice.
Unfortunately, I wasn't able to test out sideload content support or the ability to forego TouchWiz for another launcher.