The additional inch is tempting since it shouldn't make the reader quite large (the Kindle DX is a big boy!). But I really doubt the glare will have changed much in a few months. While Sony's R&D can occasionally work miracles, after years of looking at all manner of touch screens and eInk displays, I don't think they can bring it down much more as long as the touch screen digitizer layer is present. They could make the finish more matte but that would detrimentally affect text clarity and contrast.
The 16 shades of gray won't make a difference for text (2 shades are all you need for good text rendering). It will somewhat improve images. Since the Daily Reader will be targeting newspaper and magazine delivery, and those tend to have lots of images, Sony went with 16 shades. It could make illustrations in PDFs look a bit better-- generally photographic illustrations benefit more than line art. I wouldn't say the difference is huge though. When color eInk comes out or 256 shades of gray, then we're talking!
I'd say the biggest selling points of the Daily Reader will be eBook and periodical delivery over 3G and (less so) the slightly larger screen. If 3G eBook shopping and periodical delivery a la Kindle is important to you, the the Daily Reader is worth $100 more. Otherwise, save your money for books .