Yeah, for that price you do get a lot of bang for your buck. :) I agree that it lacks depth from a fan's POV - but I guess we're not the real target demographic for this book. I think it's more for people with a casual interest in Transformers as a coffee table book, and in that regard it's chock-full of information from a mundaner's POV.
If you seriously want something more in-depth for fans, and if you can read Japanese, I'd recommend getting either Transformers Generations and Transformers Generations Deluxe. There are similar publications in English, but I don't own them so I can't really comment. :o