I last saw this on a small black and white TV years ago, and this DVD looks stunning. The film quality is very high and the period detail is excellent. (Compare this to 'The mirror Cracke'd-which, though set in 1953, looks like a 1980 TV movie).
The costumes, hair, make-up and sets are superb, and the location shooting (in Majorca) is ravishing.
All of the characters are beautifully portrayed, and although caricatures, are so enjoyably played by excellent actors, and the sparring between Diana Rigg and Maggie Smith is a joy. A special mention to Sylvia Miles and Roddy McDowall. As with several other Agatha Christie stories, the outcome does hang precariously on several situations that could not have been engineered by the culprit with certainty, but just sit back and watch Peter Ustinov do a star turn with a cast ot pro's enjoying themselves immensely.