PDF is a pain to read on the majority of mobile devices. Even Kindle. Its lack of reflowing makes it impossible to adapt to various smaller screen sizes and efficiently use screen space and change text size. It's becoming a real pain point.
Haha, true, though at least on my laptop I can full-screen it zoom the content to the screen edges, and invert the colors to get dark bg/light text. It's at least serviceable that way. Nothing like it (or at least that easy) on Kindle, Android, etc. that I know of.
