Very nice work. I like the composition and the pose of your subject. I agree about removing the single snowflake blur. The oof tail looks a little out of place, but to get the dof you'd need to have that in focus you'd have to stop down quite a bit... losing even more shutter speed. I just checked, you're shooting a 1D Mk3, if he was a willing participant, I think it would have been nice to boost your ISO above 800 and get the dof you need to bring the tail in focus. (too many words, sorry) In summary, I like it.
It really looks windy. I like the light, colors and BG. I'm not so sure about the composition. I might crop a bit off the top and add just a little at the left.
If the pixel peepers are right then ISO 800 is less noisy than 640, which gives you the opportunity to stop down more to f/8 or 9.