I can reccomend it - though it's helpful to know what exactly it is so you're not disappointed when you get it.
It's part of a series of biographies of famous people from different fields where the first half of the book is devoted to biography and the second half tells the reader ways that they can get involved in persuing the career path of the subject - so the last half of the book may not interest you at all. It also is aimed for the teen/preteen age group.
But despite that, it is actually an amazingly well done biography - there's LOTS of great details on Jim's early years before he hit success with Sesame Street - things about his childhood, teens, and early 20's...so if this area of his life interests you, by all means get this book! I was actually rereading it lately and thinking this would actually be a good outline for something like the proposed Henson biofilm.