Have you guys noticed you can use a horse to climb mountains with ease? Seriously, I jumped over the peak of a mountain on a horse.

Also, does anybody have the problem that whenever you dismount, your horse wanders away? The horse I have I got from a hunter who died in the forest, and I've not yet purchased one because they're free that way. If I bought a horse, would it stay put?

Also, I'm regretting not keeping Frost. Did anybody keep Frost? Is he a better horse than the others? I noticed he's much hardier, but still dies.

Are there any uber-horses like Shadowmere? Are there any differences at all between horses from different stables aside from their coats?