This book is the sequel to Ender's Game, which is the only other Orson Scott Card that I have read. I do not really get why people are so in love with Card's work. I found this book to be fine although overly taken with its own intelligence. The book is not as smart as it thinks it is, which is Card's main literary problem. The book is a little preachy and involves a character who has a deep and telling insight into human nature. The problem with such a character is that they are not going to be more insightful than the author, and the author is not massively insightful.
The story concerning the aliens is more interesting. The alien biology is novel, but as I understand it clearly impossible. The writing is fine, the characterization is fine. All in all it is a competent to goodish science fiction novel. A respectable read, but not a life changing one, although it seems to think it is.