The production values in the sets and costumes and the magnificent outdoor locales makes these films really spectacular. But the very rich and cohesive performances by the cast are what keep these films alive. Above all Romy Schneider and Vilma Degischer as Sissi and Sofia playing the tension between the young empress and her formidable mother-in-law, are great to watch. Each has their own humanity and, actually, rich human qualities shine through in all of the other characters quite beautifully.
Karl-Heinz Boehm is excellent as the young emperor torn between his love for the fresh and lively Sissi and duty to his by-the-book mother. And Magda Schneider and Gustav Knuth are warm and sympathetic as Sissi's parents.
The restoration, recently performed on these films, has left them looking incredibly beautiful (on par with "Gone With the Wind"). And people are now able to enjoy these films in the U.S., as they have recently been sub-titled in English and given deluxe DVD transfers with bonus features. Apparently there was an assembled version made of all 3 films and dubbed-horribly-into English included in the set. But above all it is great to see them released here with a good translation and anexcellent DVD presentation.