OK, I downloaded "A Tale of Two Cities" as both a tagged and an untagged PDF (which should make a difference to how well the document reflows).
Looking at the untagged version on the 511EB first:
- With the reader set to display the width of the pdf, the text is small but would be readable in good light.
- There are four font sizes, but the three larger ones would require you to scroll right with the arrow key then back to read every line.
- The page down button pops up the "Processing" dialog, and the page turn takes noticeably longer than a full refresh using ePub.
- If you change the reader to the Reflow setting, the control of the font size is much more useful, as the text now all fits within the screen, but there are odd blank lines inserted, and the text is ragged right margin. You still get the "Processing" dialog on the page turn.
- Page numbers (from the pdf footer) are included in line with the text.
I couldn't see anything working better with the tagged pdf version in this instance.
So, my opion is that if you can get the books you want in ePub format you'd have a much better reading experience.