I'm not sure where all the 5* reviews are coming from - I've been a fan of the series for years so when I was looking for something to read on my train commute I grabbed this - maybe it is just that the pun idea is aging, but I really felt this is not a significant addition to the series - there are some good plot hooks in there but I felt as though the parts with meat got glossed over in order to get to the next gratuitous, reader-submitted pun. While I appreciate the willingnesss to build in the reader input, for me it goes over the top when it is so incidental (literally, the equivalent of watching stupid puns with no relevance to the story out the window of a bus.) It seemed like the approach was more build-up & stupid pun with a short punchline for the actual story. And the moons of Ida just weren't a concept that needed to be brought into the series, nor was making Ida the long-lost sister of a major (interesting) character (that wasn't news in this book but it continues to irritate)
I won't repeat the story as others have done that. If you are a fan of the series, it is ok, but it wouldn't be at all interesting if you don't know the series and haven't read the recent books.
So, pleasant escapism but frustrating in that there was a good story buried in there that just didn't come out.