It's really good, I binged the whole thing. But I wouldn't recommend it to anyone sensitive. Netflix issue a warning and they don't actually show any torture or killing, but watching the footage over and over, knowing what's going to happen to them is quite enough. Even seeing it once was too much for me, I'm not good right now.
I don't usually write reviews, this might be my only one. But I felt inclined to do so after seeing a lot of people critical about the ending. I don't actually think it's about the filmmakers judging you, for me it's about self reflection - is your behaviour online contributing to something bad? It is something to think about and I don't think a bit of self reflection is a bad thing.
Anyway...That's how I think about it. I'm going to go hug my cats now, because I need to.