Undoubtedly this is a very strong piece in all visual characteristics. I believe everyone can agree that you've developed the hair very well (I'm jealous!) The colours merge together like natural hair without being split to one colour next to the other; the subtle mixing of the adjacent colours really give the hair a convincing volume. You've also diligently shaded the skin to look almost lifelike with how you've diffused the highlights. If the hair wasn't enough to say "That's Rainbow Dash!" there is always the cutie mark necklace. I see no reason not to give this full count on all ratings! Very nice piece!
First off lets start by saying DAMN. I can draw hair, and I see people who struggle with it, but you did it so flawlessly. The colours look so perfect together and you definitely chose the right contrast. Shading as well, I think you did fantastic around the face and lips. Everything fits together nicely and doesn't look off at all. The rainbow necklace stands out, but not in a negative way. Usually I'd expect something more exciting with the background but even so, you made it work. This is a lovely portrait and I like the fact you didn't do anything so bold and thick, it was perfectly painted and I hope to see more of your artwork.