Truth is far more horrible than fiction!
I've watched it (also watched Rillington Place and that drama with Joanne Froggett playing a serial killer), and was chilled to the bone.
Maybe not entertainment in the usual sense and not a good idea to overdose on such things. I never read about these people because there is too much detail in books. Also can't watch the portrayal of torture, or kids being hurt.
A while back I saw a one off drama called, "Killed by my boyfriend", and couldn't get that out of my head for ages.
The other one was with James Nesbitt as the dentist from Coleraine who murdered his wife and his lover's wife, forgotten what the play was called. He was so good in that, frighteningly believably. A classic psychopath, unbothered by prison, charming and manipulative. Still alive to this day, maybe due for release soon.
I do appreciate good acting and know that actors like playing "baddies" for a change.