Really beautiful work! I especially like the wings and the armor. The shape of the plume-guard on the helmet is also pretty interesting looking. It adds some flair in just the right spot. I also like how her cutie mark is just poking out from the armor. I always sorta wondered about that, since even in the show the armor doesn't always cover where the cutie mark should be, but yet, nothing.
This makes me want to try drawing some armored ponies tooooooo... XD