I have had my Cybook Gen 3 now for a couple of weeks. I find it easy on the eyes, especially in the sunlight. I absolutely love the variety of font sizes and the fact that you can add fonts.
I have to agree with others that the page turning button needs some work. It works about 80% of the time on the first try. Fingernails are a must with most of the function buttons.
The battery life has been great so far. Much better than my Sony PRS 505. And I love the case so much better than Sony's.
But the best thing about the Cybook (compared to Sony) is the access to so many more books. The Mobipocket format makes so much difference especially since I am a very good customer of Fictionwise!

The other ebook retailers featuring the Mobipocket format have, on average, much better prices than the Sony Connect store. And whereas you can purchase multiformat books (@ Fictionwise) and read them on your 505, the big authors and new releases are generally in a DRM format.
I would give the Cybook on a scale of 1-10 an 8!