Cavanaugh makes world building on the galactic scale look easy. He knows how to build on the conflict from the first two books in the series and raise the stakes even higher. The stakes affect the entire known universe, but Cavanaugh also makes it very personal. Byron is still just as stubborn and private as ever, but he's learned to let those he loves into his mind. In this story he's got two more lessons to learn, and the last one's a doosey!
One of the things I appreciate about Cavanaugh's writing style is the fact you could read any one of the books in this series independently of the other and enjoy a good book. However, I can promise you that if you invest the time to read CassaStar and CassaFire first, the emotional impact and payoff of CassaStorm will be much higher.
I can't say enough about the world building in this series. The science is amazing for two reasons--it's understandable and so ingrained in the world that you just accept and believe every bit of it. The descriptions of the planets, ships, etc make it easy to ground yourself in the Cassan universe without that feeling of drifting untethered in zero G.