Overall, I liked this book very much. The plot was action-packed and kept me wanting to read more. The military scenes were usually very realistic. The characters were well-developed and you wanted to get to know them.My only complaint is the very basis of the book, the Face on Mars, is somewhat far-fetched, barely explained and strange. I understand that there are more books coming explaining the Face of Mars, but I found this blatent twist of reality annoying in a book that otherwise went so far to be realistic and accurate.