I sent some books to my PW3 to test this and I don't see anything that is egregiously bad. It's the same as they look in my PW2. I appreciate that the cover's aspect ratio is preserved, otherwise it would look very weird. The only one that looks very small is the one for Pillars of the Earth, but that's because I have a small cover to begin with, I imagine, at 206x345.
Here are some pictures:
http://imgur.com/a/CFJQ6
Could you perhaps post some pictures of what you're witnessing?