Reddit reviews Caesar: A Biography

Syme's The Roman Revolution is in my opinion still the orthodox text almost 100 years after it was written (1939 I think). There's several biographies of Caesar that come to mind, most powerfully Meier's and Goldsworthy's. Of these two I prefer Meier's, but I think Badian had a fairly scathing review of it published somewhere. The most recent thing I'm aware of (although I haven't read it) is Goodman's Rome's Last Citizen.

And of course there's always Plutarch, Appian, Cicero's letters (which contain some written by and to Cato). I don't think there's any substitute for starting with the ancient sources.