I did this for fun since my Note 3 does 4K video capturing. I also threw in a 5D2 for good measure! Make sure you read the fine print at 00:13 before you flame
There is an advantage to down scaling a 4K footage into a 1080p footage from a quality standpoint. Since YouTube compresses its video anyways, I thought a 1080p test from a 4K source would be an interesting match.
I shot some 4K footage on the water the other day that looks way better than what you show. Very crisp and great color. Not sure what the issue was with your shot.