Let me just say, horseback combat is awesome. What I really enjoy is hunting on horseback, chasing elk and deer, keeping pace, and putting that arrow in them at high speed. For some reason, it's a lot of fun. It's also fun to hunt Mammoth, though that takes quite a few more arrows. You've got to circle around, lest you be crushed.
It's also nice that I can kill wolves chasing after me without having to get off my horse.