It is not news that Augustus and his successors essentially ran the Roman empire as an extension of their own household. The domus Caesaris, as Stothard calls it, that is the clients, freedmen, and slaves of Caesar, served as the imperial bureaucracy. What is new about Stothard's account is presenting the history of the Julio-Claudian dynasty from the perspective of the imperial bureaucrats. He focuses especially on the Vitellii, from Publius the elder, an administrator (procurator) under Augustus through his ill-fated grandson, who briefly became emperor in AD 69 through no fault of his own. Food and gluttony, and their relation to power and spectacle, are a leit-motiv, sometimes interesting, sometimes a distraction from other things of more interest.
Stothard has an engaging style and a penchant for pointed observations. He knows the sources and secondary literature well. Some GR reviewers believe he pushed too far beyond what can be known, but I found little that can't be found in the ancient sources or readily extrapolated from them.
Whether or not the sources are always reliable is another matter. The best we can reconstruct is what people at the time believed happened.