Second book by Heinlein that I read and it just confirms what I thought after the first one: This guy's good! But I did see several reviews on a few sites that could be summed up as "Heinlein is a man of extremes, his books can be either great or awful, never in between" and that makes me uneasy about picking up one whenever that crosses my mind.
About this one... Well written, nice concept, believable cat. The bad thing: It was way too short, therefore the story badly suffered.