I think I may have liked this book slightly more than it actually deserved. Not that it doesn't deserve to be liked, its solid, intelligently written science fiction with believable characters and an interesting plot, expressed in some fairly elegant prose.
There are some pacing issues though. I ran into this with Ammonite too, its like somewhere around the last couple of chapters she just ran out of time or incentive, and wrapped everything up a little bit too quickly and easily. I'm a little bemused as well by how very interesting I found the whole sewage plant management portion of the story. Seems like that should have been less engaging than it was. I'm still uncertain whether the twist near the end was supposed to be a surprise to anyone but the protagonist, it certainly wasn't any kind of surprise to me. Intellectually I see that there are some things here that seems like should have bothered me more than they did.
The fact is however, I just had FUN reading this. I would set it down to go do something, and in the back of my head was a little warm feeling because I knew that when I got done I had reading pleasure waiting for me. I would pick it up again and be absorbed within a page or two and just happily trundling along like a kid making mud pies and singing a little song. Sometimes an author's voice speaks to you enough like the voice in your own head that you just feel comfortable and interested, flaws or not.