Thoughts on Eric Hobsbawm?

Eric Hobsbawm is an important historian who is claimed to have been a Marxist. At the same time, judging from what Wikipedia says about his book The Age of Extremes, it seems like he has maintained an anti-AES stance (I happen to have the book and was planning to read it in the future).

It is a central thesis of Hobsbawm's book that, from the start, State Socialism betrayed the socialist and internationalist vision it claimed to uphold. In particular, State Socialism always dispensed with the democratic element of the socialist vision: "Lenin... concluded from the start that the liberal horse was not a runner in the Russian revolutionary race." This anti-liberalism ran deep.

I was wondering what is your opinion on Hobsbawm and his works in general. Is his perspective really Marxist? Does he do actually constructive criticism or liberal apologia? Is it actually worth studying his approach to 20th century socialism?