Like Itras By itself, Menagerie is strange and unexpected. It is a collection of essays adding new places, rules hacks and campaign ideas.
I've done a full review on RPG.net you can find here: https://www.rpg.net/reviews/archive/17/17275.phtml
Long story stort, it is an excellent companion to the game. Being a wide collection you will find some of the detail won't suit your group, but for the same reasons you'll find a lot that will.
The quality of the articles ranges a little, some are better than others as you'd expect with such a variety of different writers. But the best are exceptional and the worse are still interesting. I didn't read anything here that didn't add something intriguing or helpful to the game.
If you enjoyed Itras By in any way, this is worth your time and money.