TV Guide offers a thorough review of Orson Welles’ film version of Tarkington’s The Magnificent Ambersons. The film is screening on TCM. From TV Guide’s review:

Though more controlled, subtle and cinematically exciting than CITIZEN KANE, Welles’s earlier masterpiece, it’s a wonder that AMBERSONS survived at all. … The film is so rich in innovative technique that it takes several viewings to note even the most essential elements. The “Welles sound” permeates every frame, with overlapping dialogue and a subtle control of volume and texture giving a natural feel to the words spoken (sometimes improvised in group scenes) and sounds heard. In crowd scenes he allows a host of gossips to function as a Greek chorus in estimating the worth of the Amberson and Morgan families.

The review at TV Guide also has some excellent links to online videos regarding the film.