Just finished re-reading for book club.
I'm giving it 5 stars, even though, after reading it twice I do feel justified in saying that the pacing does flag in a couple of places (during Raz' final conversations with Orolo, and during the Convox). The first time I thought it might just have been my mood while I was reading those passages, but I felt exactly the same the second time around.
Still, the book has more than enough 'awesome' for two or three 5-star novels, so 5 stars it gets nevertheless. With the couple of exceptions I noted, the book does a great job of presenting mathematical and philosophical ideas in the context of an exciting, fascinating story with intriguing and well-rounded characters. As well, it is frequently humorous, and has very clever use of language. It reminds me quite a lot of the novels of Umberto Eco.