This series almost, but not quite, lives up to the hype. The sets and costumes are terrific, and the subtle psychological tension gets more and more gripping as the series progresses.
Best of all is the acting: it is uniformly superb, but Jon Hamm and Vincent Kartheiser must be singled out for the exceptional depth of their portrayals, and their marvellous timing.
If anything lets "Mad Men" down, it's the heavy-handedness of some of the writing. The "it was a man's world" message is laid on with a trowel; I'm not convinced, for example, that it really was unthinkable in 1960 for a housewife to answer the telephone rather than her husband. Also, the "pointers" for characters' motivation are sometimes contrived; notably in the case of the art director Salvatore Romano, virtually whose every utterance "hints" at certain repressed desires, as though they weren't obvious from Bryan Batt's (it must be said excellent) acting.
The writing is weakest when it tries too hard to be ironic, and strongest when it addresses in sympathy the characters' secret demons and desires. The main storyline, concerning the protagonist Don Draper's mysterious past, while it may be melodramatic, is none the less moving for it.
It's not quite perfect, but this is quality TV that has the same underlying seriousness and intelligence that the best British drama (e.g. that of Dennis Potter and Alan Bleasdale) had until the mid-1990s.