I really liked Ratchet to the Rescue. Of the three Transformers stories my nephew and I have read (
I Am Optimus Prime,
Rise of the Decepticons, and this one), I think that Ratchet to the Rescue has the best message and the best story. I liked that Ratchet was held up as an example of a hero that uses his brains perhaps more than his brawn (although he won't shrink from using his brawn in a pinch). My nephew liked it because Ratchet is a Transformer that can fix other machines, which reminded him of his mechanic father.
The illustrations in this one are a little inconsistent. Some look fairly juvenile, and others are very visually interesting. Still, this is another good book in the Transformers I Can Read series, and I fully expect this book of my nephew's to become just as battle scarred as his copy of I Am Optimus Prime.