Aww! That was awesome good fun. Despite the occasional snag (every time it switched away from Sam's POV, I had to put the book down and pout for a while), I heartily enjoyed it. The world was well thought-out and imaginative, the characters were good fun, and it managed to be a little bit touching, just occasionally, before busting out laughing at itself again. 
 It stands alone well, but leaves you WANTING a sequel. I really hope there is a sequel sometime, because there's great potential for more fun. 
 You know what it reminded me of, just a little bit? A Dirty Job. It's been a long time since I read that one, so I can't lay it out point-for-point, but they have a similar irreverence overlying an unexpected poignance. That's my impression at a distance, anyway.