I also quite enjoyed the movie, but to balance out the positive reviews I'll note a few things I didn't like as much.
First off, nobody ever turns on a light. Actually they try turning on one light at one point (doesn't work for some reason that is not explained), and after that never touch a light switch again. I know they need the dark to add tension, but it got a bit annoying.
I think it might bug people who know some French that they keep saying the name Desjardins as "Dayhardeenz", and I'm wondering where that "h" sound came from. It really is a detail, though.
And lastly, while the climax was generally good, it got a little bit repetitive.
The main characters look for Deborah and the little girl for a few minutes, then find them standing together facing away. They slowly approach them and get attacked by Deborah. Rinse and repeat like 3 times. .
Otherwise, pretty solid movie with some creative plot points and good tension.