Wow wow wow wow wow wow wow wow and ten- thousand time more wow I don't know what to write. .... It's beautiful. The first time I saw it I almost cried. I... That's perfectly what I thought what looked like Luna. I love the glowing eyes awesome touch. I love the wings to, some people forget to put in the wings or to small of the wings. That's all I have to say so peace. Love. Kindness. Will all ways there, you just have to look. I hope to see more of your work UzukiNoKaze. Let's see Twilight or Rarity.
Just to expand on my comment.. This image has exceptional weight balance. The use of of color and contrast, coupled with the motion and quality of the line work is fantastic. It draws a path which leads the eye downward before swooping back up, keeping the viewer focused and it's got a tremendous sense of depth. I also enjoy the temperature balance of the blues and oranges, it can be hard to work with those colors without going overboard and losing the image in the resulting effect.
The only things that I'd change or look at to make it better would be the detail of the running horse/legs. I know it's viewed from the front, so that head on foreshortening can be tough to do, but if those front legs were raised higher, mid gallop, so you could see the faint view of the back legs striking the ground, it would give it a greater amount of depth.
Furthermore, if the wings are intended to be "glowing on their own power" so to speak, I'd add just a touch more jitter to the gradient, something akin to very soft light trails that you see in moving headlights, but really gently done.
Also, where the subject is back lit by the moonlight, a drop shadow beneath would help tie the subject into the backdrop more effectively.
But all in all, this is a well thought out composition with a dynamic presentation. Excellent work!