Movies that are made from camera point-of-view can be very hit or miss. This one hits for several reasons:
1) The acting is very well done. The people are mostly believable in their roles, and the actor playing the dad does a great job (has some of the weightier emotional scenes).
2) The use of cameras everywhere makes sense in this case. They are a group of paranormal researchers trying to capture what is going on, and the use of lots of well placed cameras would be a good idea. So, cutting between them makes feels natural, and the use of them here really adds to an authentic feeling atmosphere.
3) The paranormal activity that gets captured on film happens very organically, it's not over the top, and folks seem to respond the way their characters would be expected.
4) The story itself isn't trite or hackneyed. It's a story that's hard to predict exactly why the events are taking place, and you feel yourself wondering what's the real cause, especially given how calm in certain cases the lead researcher seems to be (he's pretty confident he knows the real cause, but is trying to eliminate other possibilities).
Overall, I liked it much more than I expected to and if you like horror films, and especially camera-POV type films, this is a good one to watch.