Dictator was a really good read and I thought Harris did a good job depicting Cicero - at least when I compare Harris' character to what I imagine Cicero to have been like from his own writing. I need to read the first two books!
I've started listening to Cicero's writing now too and making some connections with the personalities & philosophies of him & Pole. It's really interesting. I would love to 'really read' these two and Dictator so I can savor them more than I can by listening to them on audio.