I found these screenshots I had posted here when firmware 3.1.0 was released, comparing the same book on a
The screen resolution and font size is different, and there is a fault with the KEPUB formatting in 3.1.0 to do with the spacing between the chapter header and the text. But apart from the layout differences I can't see any obvious difference in the font rendering regards anti-aliasing, hinting, or anything. Having a screenshot from the save device would be better of course.