So I farmed up a horse, tried it out in 3bc, since I was going there anyway, and I suppose it was OK, but you can't fight from it, and that was what I was there to do, so that didn't work out so well, and besides, it didn't really seem all that fast, but I could be wrong because I'm not used to traveling on a horse.
Of course, once you have horses, it won't be long before you will have wolves, bears, cows, and mules as mounts. And bloodhounds for gnomes. And raptors, of course.
One huge benefit that I have noticed: where you had jerks clipping you at the bar, now you have jerks on horses clipping you at the bar. Nice.