On her School Library Journal blog, Betsy Bird called Boys of Steel: The Creators of Superman "ultra-cool." (This on top of her kind official review from earlier this year.) Even though kids immediately recoil from anything adults call any kind of cool, I will gladly accept her compliment. (Besides, of course, kids are not reading her blog.)
Random House made flash cards to showcase recent picture book biographies, and Boys of Steel is included. I believe they send these to schools and maybe even bookstores.
Boys of Steel has been nominated for a Cybil. The Cybils are the "premier Web awards for children's literature," run by bloggers. In their third year, they are already established enough that publishers submit books for consideration. A lot of books in my category (nonfiction picture books) got nominations, which makes me struggle to think of a nonfiction picture book released this year that was not nominated...but it nonetheless is an honor to be nominated! If even a fraction of the number of books were nominated, it'd still be stiff competition, so I am eager to see what happens. (I don't yet know how the process works or precisely what it means.)