I like the sketch effect, the position of the ponies but above all, are... "Anatomy"?..... I don't have the word to define that, but how the pony's body is made. Its legs and back in particular: their shape, their disposition in relation to the body, their proportion, etc... I think it is great!

... I may sound weird, but I really appreciate how you make "multicolored" ponies.

By the way, I concentrated so much on the pony's body that I forgot to say that I really like its colors (It strikes directly into one of my favorite color palettes), its mane is nice, in short, it's a beautiful pony ^^