I'd say for me this book succeeded where Game of Thrones failed. I rather dislike the idea of "gritty fantasy" that seems to be so popular nowadays, but this book made it work by having characters I could actually root for. The world is a dark one, with corrupt nobles, treacherous plots, desperate criminals and, occasionally, dangerous magic. Hadrian and Royce, the main characters, are themselves thieves, though they both found themselves on the wrong side of the law through events mostly beyond their control. 
 The saving grace of the books is the opposing viewpoints of the two main characters. Royce, much like George R. R. Martin, believes that the world is inherently cruel and that people will always look out for their own best interests. Hadrian, on the other hand, believes in the goodness of people and is determined to prove his friend wrong, both through his own actions and by bringing out the best in others (sometimes even Royce) 
 What you get is still a gritty fantasy story, but one where goodness still has a fair shot. 
 Update: If anything, this book is even better on the re-read. Absolutely brilliant.