Beyond the obvious fanservice, I think the storyline is pretty interesting, if not predictable. It's combining elements of his two previous works; the absurdity of the unknown in Gantz and the irrationality of the human condition in Inuyakishi. Put a likeable and sincere female lead who's an AV actress with massive surreal titties and a male lead with a lot of room for growth :^), it has the ingredients for, if anything, an entertaining story.