Its rare to find content that is so engaging. Perhaps the worst flaw in such morality plays or think pieces is once you know the gist or gimmick behind the show it surely must greatly diminish rewatchability.
Still that first trip through is a doozy. Capaldi is in what i see as his element or perhaps type casting if you will with tension drama and of course ethical conundrums.
Often times i find i have become a very critical minded viewer. Simple things like casting a child who couldn't possibly be biological for example is enough to put me off a show.
It can often be very little things that are deal breakers or perhaps when the production choices are so poorly executed they seem beyond careless and into insulting.
The theme of the show pays off again and again as it evolves and will definitely keep you guessing although it isn't too terribly cagey about trying to guess the ending either.
It retains a strong level of mass appeal or accessibility to its mystery and it really connects a lot of themes with its old world religious devils hour title to modern ideas playing out that are really symbiotic rather than either or.
These days i find i prefer fairly intelligent content mixed with the occasional entirely vapid puff entertainment.
I can't think of many moments in the entire series that i took issue with at all.