I realy like the artwork and the level of detail of the different traps that are described.
So for that part, the book is surely worth your money.
However, there is no rules on trapconstruction (sure they are in the DMG and "Song And Silence".
The traps you find have no calculated prices.
The advice on building puzzles is nice, but building a puzzle that fits in your campaign still is up to your imagination.
Some of the traps are smart, but all in all, I feel this book does not offer you anything.
As a DM setting up traps is the fun and joy of the game and if you need this book to do that, I think you should consider asking one of your players to take over DM'ing.
After all, what is being a DM about besides setting up traps and "ugly" encounters?
The content of the book would urge me to give it one star only, but the pro's mentioned in the first lines have raised it to two..... (doubt doubt doubt doubt....)