Different people had different opinions on Mockingjay.  A. R. Bovey seemed to enjoy the book in his review on Amazon.  He really liked the way that Katniss handled her problems.  Some times she acted outside of character, but he believes that that made for a better story.  He admitted that the epilogue might have been disappointing for some people.  However he thought that it was very fitting.  He said that Katniss had truly stopped living.  That she had given her life away when she volunteered to take Prim's place in the hunger games.  Now she was only physically living.  Over all he really liked the Hunger Games series.   However not every one liked this book.  Deniece R. Mason thought that it was a huge disappointment.  She thought that the first two books were extremely good and was very excited for the third book to come out.  She said that she really stared to dislike many of the characters, including Katniss. She also thought that Peeta's roll was so to minimum.  I would have to agree with Deniece.  Katniss really did annoy me a lot in the book.  I felt that she changed so much.  In this book I felt that she had a crazy imagination and was very illogical.  Personally I did not really like this last book.  It was really disappointing for me because I loved the first two.  I just hated the end of Mockingjay, it seemed to depressing and sad whereas most stories end with a "happily ever after" ending.

I think that these sources are valid because they are two different peoples opinion.