Well, this was the first book in this series where the title made very little sense given the actual story. It remains somewhat difficult to describe - it's the strangeness of the sci-fi conceit merged with the quirkiness of Pratchett's characters that make it both incredibly readable and decidedly difficult to take seriously (which is, interestingly enough, NOT a problem in Discworld).
My biggest...hmm, complaint is that the authors are under the mistaken apprehension that I remember things between books in the series. I don't. It does lead to a book that feels populated with complete strangers whose life histories I am expected to remember.
One book left in this series and, I imagine that when next June rolls around, I'll be just as surprised as I was this summer to discover that, yes, here's another one. I should read it.