I have read through many of the reviews on here, it's fair to say on first viewing, which I think was Christmas time a few years ago, I didn't like it, too much of a fan of the Albert Finney fan, but on the second viewing I'll be honest I fell in love with it. I can imagine when they were in the pre-production stages they came up with the 'dark' theme, it's such a contrast to the movie. Toby Jones is brilliant in the role of villain, he plays his scenes with such venom, a great actor, totally loathsome. I think I originally found the stoning scene a little distasteful during Christmas TV, but it's there to set the tone.
David Suchet is on his A game here and gives a masterclass to the rest of the cast, he is outstanding. You get a true sense of claustrophobia on the train when they are marooned, and the obvious cold they would have encountered is definitely evident. Poirot's summing up seems more as to what I would have believed in with Poirot, a sense of injustice. The closing scene had me in tears on the second viewing, it is truly brilliant.
This version is also superior to the 2017 remake, and although Kenneth Branagh was excellent as Poirot, David Suchet will always be Christie's famous character.