Bought and downloaded the Mythus PDFs. They show up with a .zip extension but unstuffit gives a folder called PDFs with nothing in it. If I open with Acrobat I get that the file is damaged and can't be repaired. Opening eith Preview (OSX 10.4.6) I get the page count, table of contents in the sidebar but each page only the top inch is shown the rest is blank.
It also took about an hour to downlaod.