The cases themselves are fairly interesting, given a very detailed build-up to the eventual murder so you can really get a feel for the people involved and the narrator does a good job of tying everything together but there often lacks detail of how the actual event transpired (understandable as only the killer knows what happened in each case but it sort of glosses over it in some cases, just simply a they killed them and that's it).
There are other issues which lead me to give this a middle of the road rating. Firstly it can be quite repetitive, often repeating quotes or rehashing the story (presumably because it was made for advert breaks and there aren't any on netflix) and the portrayal of the killer/victim seems very biased and one sided. Always describing the victim as innocent and the killer as out of control or psychopathic which may be the case but no way as black and white as this documentary implies.