A great book. First of all, the premise was terrific. I've read the fantasy take on a crime caper novel before (the first Mistborn book) but this one was done way better. The characters were morally grey, as professional thieves would be, and the story was gritty, as a story about an underworld gang-war should be. People may complain about the violence or the foul language, but if that sort of thing turns you off, then why are you reading a story about career criminals?
I enjoyed reading about the city of Camorr, as it reminded me of Lankhmar quite a bit, except with Venice-style canals. I loved a lot of the characters in the story, too; the contrarequialla, The Grey King, Jean Tannen...just so many cool characters. In future novels, I'd like to see the mechanics of the magic system fleshed out a little bit more, but that's one of the only gripes I have with this book, and it's a fairly minor one, as I thought the magic served its purpose plot-wise.
Suffice to say, I'm looking forward to reading more Scott Lynch.