PDFs work. It will reflow the text, or you can use the arrow keys to scroll around. The text size can be zoomed.
It didn’t cope with a PDF which was just images (scan of a magazine) but it will show the images in PDF documents. The options it has are “Fit Window”, “Fit Width” and “Normal // Reflow”. “Fit Window” shows the whole page on one screen, “fit width” zooms to the width.
By “landscape mode” do you mean “rotation”? I can’t find any way to rotate the screen. I don’t have a PDF printed in landscape to test it on, though.
If you have a particular PDF you’d like me to test, let me know.