Considering the very high quality of the opening books, this resolution to the "Hunger Games"-saga was a bit of a downlet.
First of all, the book was too long - it reminded me a bit of the Harry Potter books that got ever longer but with less plot. Granted, some details were added that definitely contributed to the main story, such as what really happened to Finnick and Haymitch after they won their respective Games, details which explain why they joined the rebellion and also how the Capitol maintained such a strong hold on the districts. And I also liked the overall numbness Katniss feels, the panic attacks at just smelling roses, the growing distance between her and Gale, and her realization that she loves Peeta, the feeling of loss at his being "hijacked". The comparison that the civil war is almost like another Hunger Games, with traps like in the Arena placed all around the Capitol, works astonishingly well.
Still, the scenes in district 13 drag out too long, and all the action (and their consequences!) is compressed into a few pages. Katniss is used by Coin and Plutarch, and, when the districts are won, left to die, preferably at the hands of Peeta - and if that doesn't work, killing off Prim by sending her off into war, should push her over the edge. And it does - as Plutarch predicted, but Coin miscalculated.
The book glosses over the mentionned consequences as Katniss's killing Coin is explained away by temporary insanity brought on by loss and war. I'd have wished for a more elaborate discourse here because the question of what to do with rebel leaders, of how to make the transition to peace and not just to perpetuate the status quo under new leadership, is a relevant one, as evidenced by the news every day. So this should have been better explored, because the fight isn't everything, it's the way things are done when the fighting is over that determine the future.
Overall, a highly recommendable trilogy, even if the conclusion could have been handled better.