I agree. Cats cannot be handled as standard cav. They are a specialized shock cav, designed to deliver a knockout blow. I also like using them to protect my flanks if I am fighting on the defensive. Unless you let a phalanx get a hold of them, you can smash any infantry trying to sneak around the flank. With their high defense, I don't worry too much about letting them get in prolonged melee combat. Obviously I don't leave them out to dry, but they are great for delaying the enemy until I can reinforce that flank.

With more standard heavy cav, (PC, CC, SBC) I will try to engage the flanking elements before they start to flank, but with the Cats, I don't want to run them around too much because they do tire a little easier than normal cav.

Properly used, the Cats can turn a up-for-grabs battle into a mass rout.