** spoiler alert!!!!!! **
It was a good end to the series overall :) I went through some ups and downs while reading the book (had some things I liked and didn't like) but that's typical for almost every book I read.
First, the negatives. In the beginning there were a lot of unfamiliar names thrown at you all at once. It took me a while to figure out who was who and what role they played in the story.
The ending with Gale, Peeta and Katniss was a little underdone in my opinion... They mention that Katniss would have to choose (which I figured) but in the end, Gale went to live in District 2 and Peeta returned home with Katniss.... so by default, she chose Peeta... I think the whole thing could have been better. But one of the things I like about the book is that they don't focus so much on the love story.
Katniss has clearly changed from the girl she was in the book and it is to be expected (look what's she's gone through). I understood her, and other characters, almost going through a PTSD period. I don't really count this as a negative or a positive to the book but the new Katniss made me sad but like I said, it had to happen. She couldn't be the same person from the other books. It wouldn't make any sense. Overall, Katniss is still a strong and smart character.
Some positives. Love how Katniss and Peeta slowly rebuild their relationship. She never gives up on him and I liked how he slowly started to figure out what was real and what was not (the Real or Not Real game was cute). I liked how each character had their own issues to deal with (again, playing into the whole, if they were really fine and normal, it wouldn't make sense because they have witnessed a lot of cruel and unspeakable things). I hated to see Peeta's kind and gentle personality change like that but it was within reason.
The ending was interesting and very sad with all the characters that died. I won't give it away (even though there are already spoliers) but one character's death I couldn't believe and had to go back and reread a second time to make sure I read it correctly. The ending, very very interesting and surprising. I liked it a lot. I wanted to know more if the rebels continued with their plan with the Hunger Games (starting the cycle over again) or if it never really happened...
Overall, I don't think it's my favorite book of the series but it was definitely surprising and interesting to see how everything came to an end. Really liked seeing the growth of the characters from book 1 till now.