Number one! It has a good composition and the lighting on her face is nice.
#2 - her eyes look a little blurry to me
#3 - The bright splashes of color on the two top corners are distracting
#4 - I love the layered background but the tip of her ear is cut off and the hair is almost being blown in her eyes.
ETA: Where can I get a two headed dog? She's so cute!