Be careful about using it a group with other pets. In my experience, it gets canceled any time a necro or conj pet walks thru it. The same is true with other "limited pets" such as the Warden's protecting grove, and the Furys ring of fire. I'm not sure if Swarm pets cancel it or not.
I've used it while soloing to great effect against groups of Raptors in Sinking sands. It's basically crowd control.