So "Zuko's Story" is out (although not quite as easy to find as I would have liked, it seems) and some people have read it! Who aren't my editor or co-creators! MAN, THAT IS PRETTY CRAZY!
And a few of them have had some things to say about it! If you're interested in the book but not sure if it's for you -- or, alternately, if you're like me and just enjoy reviews for books you've already read yourself -- here are a few of the reviews I've seen that might prove useful. (Note: most of these contain major book spoilers as a part of summarizing the story.)
• Anthony Castaneda for the Frensno Pop Culture Examiner
• NextAirbender for LastAirbenderFilm.com
• rufftoon on her Livejournal
If you're not keen of the film but are a fan of ATLA and are curious about the prequel, you might be interested in:
• a review by artpop on the avatar_fans community
• a review by puffysanjo encouraging discussion on the racebending community
That's it for now, I think? But let me know if I missed anything!