I read Edward Gibbon's "The Decline and Fall of the Roman Empire" first, so my impressions of other histories of Rome are colored by Gibbon's unique style of snark and knowledge. 
 Beard's work reads at times like a somewhat chatty lecture rather than a well-kneeded scholastic work, but what she lacks in polish she makes up for in honesty. Gibbon, as glib and well-turned as his "Decline and Fall" prose is, covers up some of the uncertainty inherent what we know for certain of Roman history. Of course, telling a story without too much uncertainty is fine so long as you are made aware of the gaps. Beard, who is honest about what we don't know, nonetheless draws what she can from archeological finds and exposes many interesting facts and anecdotes, and raises new questions. Overall, her history serves as a good balance to the 'been-there, done-that' tone of Gibbon's excellent tome. 
 Rome had no IRS, no EPA, no department of justice, no police force and no troublesome checks and balances. It was the ideal libertarian state! After a period of 100 or so years of a functioning republic, from the time when Caesar crossed the Rubicon, senate power decayed to 'in name' only, and then, after Augustus, not even in name. And what happened to the people during the years of Empire? According to Tainter's "The Collapse of Complex Societies" (see my review for details) the rich got steadily richer and the poor got steadily poorer, and eventually the people got on with life as best they could under the local protectorate rather than under the Pax Romana.