I'm split on which mech horse design looks better. The top one is better detailed, but it's just a little too bulky in my opinion. The bottom one doesn't seem as well proportioned as the top. If I had to choose however, the top one is what I'd go for. Hover bikes have been confirmed for a quite a while now.
glitch horse! glitch horse! glitch horse! glitch horse! It roams around the planets, the thoroughbred of tin. It got the application that you just sent in!
I think the bigger horse looks better, but a side-by-side comparison with the humanoid npcs would be better. I'd also move the 3 upper lines of the lower part of their hind legs a bit more behind, to give the impression of an angle [I don't think horses hind legs are totally vertical from that big bending point onward, but that's just my opinion]