Trying hard not to spoil:
A lot of review criticized the 3rd act. The criticism centered around it being an abrupt change of tone, which is true. Most readers expect the Hunger Games would end in the 3rd act being the climax and are disappointed that is not the case. My view is that the 3rd act, despite being slower in pace, provided a necessarily developmental phase for Snow and connect him to the Snow we know (and hate) in the original trilogy. Overall it's a great story and imo much better than Mockingjay. Can't wait to see this as a movie.