I had champion rouncey,but you need to have 7 riding to make it awsome.
i had champ courser speed is interesting but there is not much open maps,and low manouver is what bothers me. It can't realy accelerate fast enough like arab do. But archers can't shoot you that easily cuz you are very fast.
i had champ destrier,he is too expencive to ride every round,like the thing that have lots of health,but i dont like his low manouver,because i don't like to go fast,i like when horse is agile and can accelerate very quick cuz you need that when you fight vs spearmen and 2h footman with gs or other lance cav.
i tried ordinary arab warhorse and it is nice horsie,but it dies from one arrow. So that is realy pissing me off. You can't charge anything if there is archer around. But it is awsome when you move very slow arround spearmen ,and then press w and horse accelerate from 1 to 100km in one second leaving him with no time to release his attack,and stab him in the face.
I don't like heavy horses,because they are too expencive to ride,yeah you can take a lot of arrows,but it is horse for 1h or 2h cav. I am not very good with 2h,and 1h cav class.