[FJames]

The Kobo eInk e-readers are just not the right tool for reading pdf. It's more of an emergency fallback capability in case you are stuck somewhere with only your Kobo and you need to read a pdf document.

For books, they can't re-flow the text to fit the screen, so you are stuck with the original page image. It's always either too small or too big. You can adjust to a custom zoom level, but it takes several steps and you have to do it again on every page, so way too slow to use for reading. Using the quick tap zoom to 100% means that you have to pan around the page very slowly - again, not useful for reading. Why wouldn't you just do the sensible thing and convert to epub using Calibre?

As for pdfs with lots of images and color, you'll want to read those on a color tablet.