> What distinguishes the upcoming Sony model from others already in the
market?

The display technology appears to be new. This is from the promotional
materials:

What is E Ink(r) Technology?

The Sony(r) Reader's display uses E Ink(r) - a significant improvement over
CRT and LCD technology. Instead of rows of glowing cells, E Ink(r)
microcapsules actually appear as either black or white depending on a
positive or negative charge determined by the content. The result is a
reading experience that's similar to paper - high contrast, high resolution,
viewable in direct sunlight and at a nearly 180-degree angle, and requiring
no power to maintain the image.