I saw it on DVD a couple of years ago. (That was before I got a high speed internet connection.) As I recall, I didn't find it all that scary, but that was probably from a combination of its having a low-budget feel and its being often from the killer's view point, making it somewhat sick, both of which made me not want to get into it too much. I'm sure that if I saw it in a cinema, where  it is harder to distance yourself from a movie, I would have found it pretty scary.

I guess I like my horror and violence to be highly aestheticized, like in Argento or The Shining. If it's done in a realistic way, I generally find it too disturbing to be fun.

Speaking of documentary-style horror, have you seen Cannibal Holocaust? I'd say that pushes the genre as far as it has ever gone. Definitely not recommended to Ronald Rutherford. Unlike And Soon the Darkness, this movie has a political message (but it contains one scene that I knew about that I skipped over).

And from Germany, we have Der Todesking and Schramm. Again, not recommended to Ronald.

A bomb, H bomb, Minuteman / The names get more attractive / The decisions are made by NATO / The press call it British opinion -- The Three Johns