While an entertaining, fast read, The Devil's Mask lacked contextual details, and some of the side-plots went undeveloped (Bright's relationship with his bride-to-be and her family could have used some fleshing out, for example). Short interludes from a different perspective pretty much give away the game right from the outset, so by the end there's little mystery left.
Overall, good for a weekend afternoon's entertainment, but there are certainly better books in the genre.