The weakest book in the series, but still entertaining.
Most of the book is arena battles, and they're written well. The character development is good, but the plot is rather weak, with major elements mentioned in passing but never developed. The denouement is a bit trite and seems intended for a setup for a new series. (I don't see any evidence of such a new series, FWIW.)
In spite of the flaws and the weaker final installment, I would recommend the series. It's a snappy read and entertaining throughout. It's not a masterpiece, but it's a well-crafted ride.