"full of passion"
Xenocide is perhaps the most overtly philosophical of the Ender Wiggin series so far. But the philosophy in the book serves a purpose to move the story forward and develop characters more.
In addition to making you think, it also makes you feel. Xenocide is told with the same passion as Ender's Game and Speaker for the Dead, and it is filled with just as much emotion and understanding. Yet it is also very much its own new and wonderful story, and not at all just a revisit to the same old themes of the first two books.
Note, however, that, as the author himself mentions in a short commentary at the end, this book is actually the first of a two part series (the next book is "Children of the Mind"). The ending of this book ties up some threads of the story, but not all of them. If you think of it as a stand-alone book, you may be disappointed. But if you think of it as the first in a two-part novel, then you'll likely be dying to get your hands on the next part of the story when you finish.