Hannibal seems to be a fairly balanced leader in the games I've encountered him. He techs well, builds big armies, and expands fast.
Shaka seems to do almost as well as Hannibal, but is far more agressive.
If I'm close to Monty at game start, I'll rush him everytime. One single time, however, he was adjacent to me, but too far away to rush. Oddest thing though, he peace vassaled and stayed a loyal, if not too competent member of my vassal coalition, for the entire game.
In my experience, Ragnar is always the one to watch out for. I can recall very few games that he's been in, that he failed to attack me at some point. Even from another continent. I can remember only one game when he didn't, and it was odd. I was at war from the end of the classical period onward, w/only brief breaks to reinforce/upgrade. In retrospect, this was probably because Ragnar was also at war with the AIs that I was conquering. That brothers-in-arms diplo bonus must be big. That game was my first noble domination win.
