I completely loved the first two novels in this series, but this omnibus broke my heart. I was all ready for a fantasy + time-travel story with an epic ending, but the way it finished left a bad taste in my mouth. The fourth novel is what killed it for me. Sad, since the first 3 were so damn good. Her writing style was great and her characters where lively, which is probably why her seemingly swift an critical ending of the series really upset me.
Here's an exciting fantasy tetralogy with all the right ingredients: four elemental dragons (Earth, Air, Fire, and Water), each with a human companion. This series takes us from medieval Europe to the distant future, as the world is caught in a war between the forces of greed and fanaticism, and the dragons and their guides and allies who seek to restore the proper natural balance to the planet.