I don't know how many times I have been looking through the powers to find something cool to annoy my players with and when I get to the Summon Ally Power and think: "I need a way to balance this". This supplement tries to address exactly that.
As a GM it allows you to swap things out and make foes that are much better suited the story you want to tell. For example I made Lamashtu that could summon a wolf, a donkey and a reed boat. And as a player it gives you a way to really use your fantasy and summon some awesome stuff. And it gives a framework to work with together with your GM and not use days arguing over Traits and Edges and still ending up with a gimpy reskin of the construct.
Furthermore this does a great job of analyzing the Summon Ally Power in relation to all other aspects of the game. It shines light on cool synergies even before introducing a single line of new rules.
I also want to say that by fiddling around I have even plugged this into the Shape Change Power and Beast Master Edge.
[5 of 5 Stars!]