What I really enjoy about this series is that, even though it's complete fantasy, it's totally believable in it's world! And oh my gosh what a world! Marie Brennan has built this amazingly intricate world with not only dragons, but also it's own politics and layout and cultures! Sure, there are a lot of similarities to our world, but only enough to be vaguely recognizable.
My favorite are the characters. While they're all well rounded and entertaining, or heroin is what makes these books so worth it. Isabella Camherst has grown up a bit since we meet her in the first book (or maybe matured is a better word?), but she's still this kickass woman who refuses to bow down to society's expectations. She's also not perfect, although she does tend to be the hero... but it's usually an accident!
Unfortunately, a lot of the adventures to be had in these books rely very heavily on politics (albeit imaginary)... I'm not a fan of politics in general, and a lot of the time I struggle to keep up with these imaginary ones... Which is the only thing keeping me from giving it 5 stars.