Found footage done right
This movie seriously creeped me out, and I'm really impressed by that. I watch a LOT of horror movies in all kinds of styles, and without question I would say this is one of the top 3 "found footage" style of horror movies I've ever seen.
The blending of actual interviews into a fictitious story line was done very well, and the pacing and "down the rabbit hole" style of the story was wildly effective.
Most importantly, this is one of the few horror movies I've seen where you actually like the characters. So often we're introduced to a bunch of jerks you're just waiting to watch die... this had generally likeable normal friends, which made for a much more engaging film.