I love BOTH, but Umbreon holds more motion, more expression, and there's something that looks a little.. off, in Espeon's muzzle/face. The background in Umbreon's image is also my favorite of the two by far, and the reflection is a nice touch. c:
Both are awesome,but I didn't hesitate to choose Umbreon because; 1)these is movement and you showed that in your drawing and painting as well. 2) you used a floor that reflects on it everything;lights,colors and the image of that character,realistic indeed.