Ask me in 2-3 weeks...
For me, Mobipocket is the third choice for ebook format (after HTML and RTF), so still being a bit rough around the edges in mobi format doesn't disturb me. The Cybook doesn't handle RTF at all, doesn't handle separate file HTML, and still get lost sometimes with italics in HTML single file. So for me the bar is set very low. But I won't know until I get me BeBook and can compare side by side...