I recently got that book. I really enjoyed it -- it's cute and fun. They threw a lot of details into the illustrations that show a great juxtaposition between Superman's crazy life and Clark Kent's very mundane life. (I think the bottle city of Kandor was somewhere on Clark's messy bedroom floor, if I remember correctly.)

I think the book can stand on it's own, but I don't think it would be as entertaining if I didn't have at least a passing familiarity with the book it's based on.

"It is a remarkable dichotomy. In many ways, Clark is the most human of us all. Then...he shoots fire from the skies, and it is difficult not to think of him as a god. And how fortunate we all are that it does not occur to him." -Batman (in Superman/Batman #3 by Jeph Loeb)