A fun new faction to include, and rules for efficiently handling groups of enemy combatants, which can quickly become tedious as the author notes. As one of the other reviewers pointed out: There's flexibility here to apply these rules to any group of low level threat beyond your classic swarms (e.g., being shot at by a lot of untrained people with guns).
Flavor note: In keeping with the Hands controlled by Heads theme, when introducing this into my own game, I may adjust Gyges's title to something like Overmind, as opposed to Overseer :-)