Short Review: I really liked the book. I have only a small reason for not making it five stars, and that's because of the way my mind is made. It's very philosophical, so be warned, but I enjoyed those parts most.
Longer Review: The only reason XENOCIDE doesn't have five stars is because THE ENDER SAGA, aside from ENDER'S GAME, isn't as good as Bean's story. To me. I've recently discovered that a HINT of politics in a book makes me wild to read it. It's possible that THE ENDER SAGA is better written, but I frankly don't care.
XENOCIDE is an excellent book. My favorite characters were Miro, Jane, and Wang Mu. Perhaps I liked Miro because though he spends a lot of time moping, it's the moping that allows you to know him so well. And when you truly understand someone, you love them.(Yes, that's a concept used in the saga. I think it's true.) Jane brings in politics with her interactions with everyone--this means I like her. (Why did it take me so long to realize how obsessed I am?) As for Wang Mu, perhaps it would be better to say that I liked the side of the story that had her in it because of the way it was written which appealed to me.
Overall a very good book.
I wouldn't recommend it to anyone under sixteen, same as with the other three after ENDER'S GAME in the series.