Instruct: Classify Amazon reviews into positive or negative sentiment
Query: The series is officially unsustainable at this point

Wow, that went downhill quick. Alvin is no longer a vaguely interesting character in a well-drawn world, but a blatant Christ figure with nothing at all for the reader to relate to, a figure of such saccharine goodness that all obstacles just collapse at his approach. It's a shame Card felt it necessary to inflict this on people who enjoyed the first two books and put up with the next two.For good Christian allegory (if that's your cup of tea), get CS Lewis' Narnia books -- the story stands all by itself.