Despite
smaug's sound counsel, I opted to continue with my Cavalier. Oh lawd. Outside the first charge, the mount AI goes berserker mode and you have no control. Since I am playing only on normal, my character zooms across the battle critting shit. There is no tactics, only horse bites. This is amusing for the moment, but I know that I am toast when I face the first boss or hard encounter.
It is a shame that it is so bugged, because of all the pathfinder classes I really enjoy this concept. It's probably far from optimal, I do get the sense that I could replay the class around different aspects (charges spam, single enemy challenges, or group buffing).