Hubbynz: the arms aren't too bad, some of them could be better. Overall, I'm happy with the quality of the miniatures. The biggest problem I noticed was the lack of detail between the riders' legs and the stirrups. I imagine it's mainly due to the molding process.
Beefcake: I don't think they have any at a slower gait. The horse bodies come in two halves and are all interchangeable, so there is the possibility to get what you want.