It was...okay. I think if it were up to me, it would have been a 2, but I can't deny that my kids (mostly) really loved these fairy-tale-like stories to illustrate the Proverbs.
What I didn't like about the book was that the ostensible point of the fable--to illustrate a proverb--often got lost. Often I think this is because the author was trying to be too clever. He would mix in allusions of other Bible stories or name his characters with biblical names that honestly, for me, confused the issues at hand: trying to do too much at once. ("Right, so this guy is named David, so he's going to do something David-like... oh. No? Okay...") Then, sometimes the descriptions were off, describing something good with a metaphor that both I and my kids found off-putting. Granted, in a fairy tale, things are often not what they seem, but his descriptions of good things gave me a sour taste often enough that it bears mentioning.
An example of both of these problems is my sorest spot of the book, the story of The Monster's House. We had to have a long talk after that one. It made them uncomfortable, and not in the challenging-to-their-faith way. They were horrified and disturbed by the idea of the God-figure literally turning people into bricks to build his house--and that being a good thing. I get that Leithart was trying to incorporate the idea from the New Testament that the church body is being built into God's temple. (Again, trying to do too much was the downfall. Sticking to the proverb would've been better.) So we had to have a long talk about what he was trying to say and how he failed in saying it (a brick has LESS freedom, LESS individuality, whereas someone united to Christ has more of both).
I want to end on a positive note, because the girls truly did enjoy this book. So I'll say that our favorite stories were the one about the walnut with the fairies inside and the one about the wise woman taming the lion. They would never let me stop before the stories were finished, so we read a whole story each day.