PC
reading is for:
when I need to RTFM

Editing EPUB's
Spot checking EPUB's
LCD Tablet:
Looking at the Color Covers (using CC)

When the

EPUB crashes on my PEz (and I can't find any EPUB or CSS errors)
PDF drawings/datasheets for hardware I am installing
My Pz is my #1 reader because the page turn buttons are in the
right place for me.
The K4NT is #2 but the Page buttons are
just in the
wrong place for my XL glove sized hand