I liked this book despite some obvious flaws. The characterizations, for the most part, weren't extremely deep, although I really liked the character of Vin; she was damaged and confused and was not your typical "Chosen One"-style hero. The majority of the rest of the cast fall under the "lovable rogue" category, and aside from their Allomantic specialties weren't very well fleshed out. The "ultimate caper" take on a peasant revolt/revolution was fascinating, but I felt that more attention could have been paid to the revolution itself and less to the balls which Vin repeatedly attends - not to say that the politics of the noble houses weren't interesting, merely that Sanderson spends a good deal of time describing Vin's various outfits and the architecture of the keeps and ballrooms(as a carpenter, I could tell he clearly doesn't know much about architecture or construction, so those parts were particularly painful for me to read).
What really shone about this book was Allomancy. A very inventive and unique system of magic, I was constantly surprised and impressed with the things Sanderson thought to do with it. It shows that he put a great deal of thought into his system, which is fairly promising with regards to the other books in the series.