Well, I've now read a selection on sunspots, and also his letter to Castelli (a monk and mathematics professor). I'm in the middle of his letter to the Grand Duchess Christina. The man clearly likes to argue, he clearly knows when he's right, he clearly knows just how wrong his enemies are, and he has an incisive intellect and wit.
Shame he died so long ago. I'd have enjoyed hanging out with him. And since he's Tuscan, he probably had awesome culinary taste.