I like this one, too. Great color, lines, curves, and composition. You were probably the only one taking blurred shots -- at least intentionally -- and the result is certainly very pleasing.
The blur turned out great, showing the racing action very well. I really like that the lead horse is quite clear and that the other horses seem blurred a bit more, really making the viewer feel how that front horse is out ahead of the crowd. The white curved line of the inner fence holds the composition of the horses together as well as keeps the eye moving forward. Love the brights & whites of the jockeys and the deep green of the bkgd. The dark edges gently keep the focus on the racing horses, and I like the additional curve of green at the top, mimicking the white railing curve.
You do a marvelous job with blurs and motion. The colors the white line and curved green lines are strong and add "pow" to this image. Why do the lines at bottom left curve downward and the ones in upper right curve upward? I'm looking at this after having seem the photo you posted at a later date. I prefer the other photo, probably because the horses are larger in the frame. But, both are good.