I personally don't like the border, but...
The sense of motion you have captured here is glorious. :) I can just about feel the tremendous, rolling power and grace of the horse. Somehow the colors and high-contrast strenthen this impression, although I wonder how this would look with just slightly less contrast...Very beautiful!
Hey, I like this! My only suggestion would be to crop more off the right so the horse's head isn't so centered. You obviously found an audience who appreciates blurred motion shots, since you got 3 10s!