I'm probably
the manga-expert around here.
I've been using the PRS500 and now am using PRS505 to read manga, but I convert my manga completely to LRF. Although the reader can read pictures and pdf, both formats are not so good for the reader.
Using pictures, it's hard to navigate.
Using PDF, the size is a problem.
Converting PDFs to LRF, that would negate all problems. If you use a tool like rasterfarian, the contrast will be increased compared to normal pics. And the generated LRF will be a fraction of the PDF file.
It's a bit outdated, but this review will give you a headstart:
http://hightech.afmag.net/reading-ma...ve-review.html
Oh, nekokami, I've created manga2pdf for the sony reader actually, so you can find it in the sony reader's forum. (I've chosen PDF as an intermediate format, because IF I ever buy another reader, I can easily reconvert the pdf to the correct fileformat)