It has good ideas that work with the Mass Combat system of the Savage Worlds core book. It add a bit more details to quantify the strength of irregular troops, especially common in a fantasy setting. And also takes into account the abilities of a Wild Card as well.
It does this without requiring a lot of tables and calculation. If you're running a quick mass combat session, you can skip the steps in this book, but if you have some prep time, then this book's contents are a welcome addition.