Allen serves up a nostalgia that was utterly of its time; he incarnates an idea of the city that, even now, remains as strong as its reality and refracts his disappointed ideals into high existential crises.
In "Manhattan," Allen has more to say about people, relationships, and human nature than he does in "Annie Hall" . . . but what he says, apart from a handful of hilarious lines, isn't as consistently funny.
Manhattan is Allen's most fully realized film, especially in the way perspectives are developed. It's the rare movie that can be watched from a number of different points-of-view, without feeling cheated.
Arguably this is Woody Allen's masterpiece, in which he revisits the themes of his bittersweet features and refines his distinctive serio-comic tone, not to mention Gordon's Willis brilliant b/w imagery and George Gershwin's evocative score.