This film was on the edge of greatness IMO, but was merely good because of a few setbacks. I had problems with two things:
(1) The Strangers were 2 females and 1 male. I just can't buy into the fear factor of it; make it two males and one female and then we're talking.
(2) The voiceover at the beginning with the "inspired by true events" cliche was unnecessary. I would have eliminated that and the Mormon boy thing completely. Start the film with the first scene with Liv and Scott. End it with Liv crawling towards the cell phone (in the Unrated version) and that's it.
In my opinion, if these were eliminated from the film The Strangrs is a minor classic for horror, but because the film undermines its intimidation by having 2/3rd of the Strangers women and a cliche voiceover that takes you out of the experience, it falls back a bit.