The facial expressions are very bold, and credit is certainly due there; it can be extremely difficult to properly arrange ponies mouths and features to fit such a wide grin, but you pulled it off very well. That said there are still some errors. Their eyes are microscopically to close together, especially Sweeties. The mouths seem to originate too far from the tip of their noses. The line running through scootaloo's hair ends a bit too abruptly near the tip (in cannon it ends on the bottom too), and the bottom curl of sweetie's hair seems a bit squarish. Sweetie Belle's horn and hair also seems pulled a bit too to far down her face. I would also suggest having their cheeks intercept the corners of their mouths a bit and perhaps a more colorful font. None of these are deal breakers though, and to be honest took quite a bit of staring at references to notice. Good job, and as always, you rock!