Rely on Horror: Silent Hill Book of Memories is a game that has been hated by many since its announcement. Not because of the game's quality--which couldn't properly be judged at the time--but because of what its existence meant to uptight purists of the series. Book of Memories somehow tarnishes the series in a way that only those who are still hung up on the departure of Team Silent can see. BoM is blasphemy in their eyes; it shouldn't exist. This kind of asinine complaint is unfortunately the most prevalent opinion of the game—pre-release mind you.
Book of Memories is a spinoff. That's it. It does not deserve to be condemned as if it has somehow lessened the value, emotional impact, and depth that Silent Hill 1-4 offered. It's just a game meant to entertain people. If it offers more than that in terms of its canon story, then great. Let's just give it a chance, shall we? With the release of a demo we now have a chance to play it for ourselves and judge it properly.