You can get an idea of how the PRS-505 will display PDFs using
Sony's Windows ebook Reader. The Sony is the only EInk device that reads Secure Adobe ebooks (sometimes called PDFs), but for standard letter/A4 PDFs the iLiad's larger screen is typically better. However, the PRS-505 will attempt to reflow the PDF which the iLiad will not do (unless you import the PDF into Windows MobiPocket Reader and view the resulting MOBI file on the iLiad). The success of reflow is highly variable though.