If that is the E-Ink technology that was at siggraph it will be nice. I would consider it if it is open to any text documents. If it displays only DRM content, I will pass.
Mostly I don't want it for books. I love books- what I think it would be great for are newspapers and magazines. I could have instant access to the New York Times every morning. It's for things you don't save. Like The Economist. Not for books. It would be blasphemy to use this thing for books.
I have a theory that our society will be a complete mystery to the future inhabitants of Earth, because there will be no physical records, and the ones and zeroes of our history will be indecipherable or lost in the ether.