I thought it was excellent, especially in terms of the acting and single shot filming (seriously, how the hell did they do each episode in one shot?). It was very clever in what it did and didn't reveal - like not showing the kid throughout the final episode and purely focusing on the family's reaction.
The episode with the psychiatrist was really fascinating too. I'm not sure how accurate it is, but I loved seeing the process and the raw emotions it elicited.