My biggest gripe with Voyage is the silly restriction to 4GB and no SD card in order to make PDF viewing far less likely. A lot of scientific papers are available in PDF only as well as older books and magazines and they are considerably larger than Kindle's own format yet preserving layout nicely, so they are my preferred media. I don't care about uneven lighting (yellow-blue cast across the screen) as I turn the light completely off.

Is there any e-reader with "retina"-style e-ink that is optimized for viewing PDFs/PostScript and allowing a SD card?