The entire World of Darkness line is, obviously, not wholly intended for the faint of heart. Even if a troupe wishes to gloss over some of the darkness, it is hard to work around the fact that vampire characters feed on mortal human blood, werewolf characters (almost) inevitably create swaths of violence and even 'standard' mortal characters are mired in a world which is, well, dark.
Therein, obviously, lies the appeal. The mirror that the game line holds up to the real world may be distorted and ghostly, but there is a certain escapist fantasy to be had, all the same. WOD Slasher, however, may not be for all paritcular tastes and, of all the titles, it may well skirt the closest to being in the realm of questionable taste.
Granted, human beings in the 'real world' who descend into murder rarely do so with such operatic glee, but the fact remains that this effort does deal (at least superficially) with human evil, as opposed to the sort of fantasy evil that is more apt to be found in the more overtly supernatural creatures of the night.
That having been said, and presuming that you are not apt to misinterpret the content of the book, WOD Slasher is a tremendous addition to the line, both for the purposes of crafting compelling and frightening adversaries and also for the chance to -- for a time -- drop the facade of morality (or humanity or harmony or whatnot) in favor of taking a turn 'behind the curtain.'
The slasher mechanics are well considered and, although the book leans a bit more toward Hunter in its sense of connections, the rules and characters that the new systems generate could easily filter through any of the core lines. In the usual, bankable White Wolf way, the book is exquisitely laid out and well designed, striking an excellent balance of game mechanics, (pseudo-)historical tidbits, character and small pieces of atmospheric fiction.
An excellent resource for the game and one that can be surprisingly intense but, perhaps even moreso then the rest of the line, probably not for younger and/or sensitive players.