I'm factoring in the fact that this is a YA book in giving it such a high rating. There are some plot holes and twists telegraphed in an unsubtle fashion that I'd consider amateurish in adult sci-fi, but for a book aimed at teenagers, I can forgive them. (Hell, I like Harry Potter
That said, you should know that this is a book in which children are forced to fight each other to the death, and while because it's a YA novel, the violence isn't described in graphic detail, it's still quite grim.
Others have noted that the premise is not original: Battle Royale
and The Running Man
have covered similar ground, though aimed at older audiences.
I liked it: although a few parts of the story and the society stretched my credulity, the author carried off a rare combination of dark satire and gritty realism, and the characterization was quite good. The heroine is a bit dense at times, but she's a teenager, so that's not wholly unbelievable. Other than that, she was an engaging, sympathetic, and believable character. I found most of the characters to be quite well developed (although a few were, deliberately, almost caricatures).
There aren't a lot of surprises in this book, but even when the expected happened, my stomach was in knots waiting for it. The author gives us a rather ambiguous ending demanding further resolution: both for the main character's personal relationships, and the horrible, dystopian nature of the society in which she lives.
I almost gave it five stars because I know I am going to start on the sequel right away to find out what happens next, and because at the end of the story, I really cared about Katniss Everdeen and her loved ones. However, I still believe there are certain weaknesses in the novel that, YA notwithstanding, merited knocking off one star.