I can unreservedly say that the recent version is superior to the older movie with Albert Finney. That is not to say that the classic version was a bad film to begin with. As had been the tradition in the past it had star-studed cast. Ingrid Bergman was even nominated for an oscar for her performance. Albert Finney was OK if a little bit over the top.
The new film has only Barbara Hersey and Jessica Chastain and of course David Suchet as top tier stars yet it is a wonder of atmoshere, pace and dark undertones. Suchet's performance is among his best as Poirot. He conveys perfectly the ambivalence between his utter dislike for the victim and the evil he represents and his staunt objection to, however rightfully, taking the law into one's hands. He comprehends, not without sadness, that justice is not always served. Through his mesmerising performance the film acquires more gravitas. As usual all production point are faultless as is the representation of the 30's. Delightful and edifying movie!!!