While his approach is necessarily "broad sweep", Hobsbawm avoids bland generalisations, working into his analysis specific events and details, statistics, provoking facts, and even the occasional personal anecdote. He is as much at home describing how radio changed the lives of the poor, sketching the course and implications of the Spanish Civil War in five pages, or explaining the effects of the world economy on subsistence farming. Most importantly, he is never dull. Age of Extremes also includes a really excellent 32 page selection of black and white photographs, which would make a nice photo-essay in its own right.
There are certainly things one can quibble about. Hobsbawm's own area of specialisation is the nineteenth century and Age of Extremes is based almost entirely on secondary sources, the limitations of which are occasionally visible. A brief explanation of Gödel's Theorem, for example, is confused. Hobsbawm's own interests and biases are also obvious: most obviously, not everyone would have devoted so much space to socialism (and some consider him insufficiently "anti-communist", despite his incisive forensic analysis of the failures and disasters of communist regimes). Such problems would arise for anyone attempting to paint on such a broad canvas, however, and they barely dent Hobsbawm's achievement in Age of Extremes.