The horse is absolutely lovely, and a fine example of the breed. The way you captured the facial expression, the eyes, the curve of the neck is all really just dead on. I also like how well the background complements the horse's colors and the mood of the piece.
The only repetitive error I see in any of your work is the 'tad too long faces' between muzzle and eye. That's a common conformational trait in Saddlebreds - but is different for each breed. With the rest of your work I see a trend of self-correction that is wonderful. Keep working it!