[efreak]

I read ebooks on my Nintendo DSi for several years when I was in college; The low-resolution screen combined with my need for glasses (and dislike of wearing them) made reading PDF files unbearable. Later on I got a cheap android tablet and reading PDF files was easier, but still required constant panning and zooming. Today I use a more modern device (2013 Nexus 7 or 2014 NVidia Shield), and I still don't like PDF files. I usually open the PDF in word if possible, save it in another format, then convert to epub with calibre, and dump the other formats.

Epubs in comparison are easy, as all it takes is a single tap or button press to continue. When there's no DRM on the file (thanks HB, Baen) I read in FBReader with custom fonts, colors, and text size. It doesn't hurt any that the epub files I get are usually smaller than the PDF version of the same book.

Personally, I think the fact that Calibre's format converter has so many device templates for PDF conversion says a lot.