The book is somewhat reminiscent of the old PBS series "Connections". It is well-informed history lite. Nothing is gone into too deeply, but Bryson has done a lot of reading, mostly in secondary sources, and also, perhaps more importantly, actually talked to a lot of academic experts. He also traveled himself to some of the homes he discusses, including George Washington's home at Mount Vernon and (my favorite) Thomas Jefferson's home at Monticello. There are also, on occasion, discussions where Bryson is quite honest about differing interpretations in the literature or simply an absence of evidence on particular questions.
Bryson's interests in architectural history and in the history of language come through strongly. He is not much interested in social science, other than a quite interesting discussion of the dangers of stairs. There were a few bits where I thought he could have done a much better job of indicating whether the particularly bizarre behaviors he was discussing applied only to the rich, or to the rich and the upper middle class, or more broadly. One might call this a lack of nuance and detail in places.
The NYT reviewer seems to want to mock the book for being too much in the way of beach reading for people with multiple NPR totebags, but holds back, probably in light of the fact that this is the same demographic in which the NYT itself specializes. Still, the review gives a clear flavor of the book, and one not dissimilar from my own, as outlined above.
Recommended if you are in the mood for some history lite.
Oh, and the notes are here, rather than at the web page listed in the book (at least, in the Canadian edition of the book).