Originally Posted by HarryT
Don't use PDF if you can possibly help it. PDF was never designed to be an eBook format, and it's not very good at all for the task. The problem is that most PDFs are formatted for an A4 or US Letter page, and there's just no good way to display them on a device with a screen 1/6th the area of A4.
I would rather say: for manga use PDF. For ebooks, use PDF if you can have a PDF that's the right size for the screen only.
There's already several tools capable of creating a PDF or ePub manga for the PRS-505, and they all handle things such as resizing the page, conversion to 8 colors etc...
Honestly, reading a manga on the 505 is a nice experience and you don't have to wait that much for the next page to be displayed. Scaling down the image is necessary, changing the color depth is not. If you're in switzerland, now that the 505 is available in the UK it might be a better deal than from the US.