Absolutely terrific. Sure, I'm interested in the subject matter, but that actually means I'm more likely to be biased against this: I know more about the topic and will have my own opinions! Instead, this is a wonderful read, and throughout I was impressed by just how good the analysis was. Rather than falling into the common pitfalls of simply writing about how "good" a show is and listing funny bits, or rehashing biographies of popular stars, etc., Austerlitz actually sits down and lays out a case for the ways in which a particular sitcom moved the form forward, the influences upon it, and those that came after.
It's almost an Art Historical approach: context, style, technique ... and I hope others who write about media will read this and see the value of it. An example: he points out (which I noticed but hadn't considered) that Arrested Development really initiated the technique of someone mentioning something and then a rapid cut-away for only perhaps half a second (perhaps longer) to a relevant shot, e.g. "I haven't felt this good since space camp" followed by two seconds of a child actor smashing dioramas at space camp with a baseball bat. Austerlitz would mention this is somewhat related to how HBO's Dream On would cut to clips from old TV, and point out which shows would follow (e.g. Community).
Of course the Simpsons probably did it first!
And it doesn't hurt that I agreed with all of his included examples, although I would have moved Heaven and Earth to get Bewitched in there ... so it's better that he wrote it, because as much as I love Bewitched it wasn't ground-breaking or definitive in the same way as his examples.
On the down side: a couple (that I noticed) of factual errors that are probably the result of an over-confident memory, e.g. he thought cousins George Michael and Maeby sang "Afternoon Delight" but it was his Maeby and Uncle Michael, followed by George Michael and Aunt Lindsay. They're of very minor consequence and didn't affect my enjoyment one iota.
(Note: I'm a writer, so I suffer when I offer fewer than five stars. But these aren't ratings of quality, they're a subjective account of how much I liked the book: 5* = an unalloyed pleasure from start to finish, 4* = really enjoyed it, 3* = readable but not thrilling, 2* = disappointing, and 1* = hated it.)