@JohnD - As almost anyone on PSG can verify, I have a reputation as quite a critical viewer / reviewer. However, I try to take into account the fact that many (most?) tweak jobs posted on PSG are done to illustrate a specific, often simple point, not to achieve perfection. As Hershey pointed out, there are limitations on one's time, limitations imposed by the quality of the starting image, limitations imposed by the necessity for tact and reasonable expectations when dealing with someone who may have less experience in PS, etc.
In this case, of course, if a highly skilled photoshop artist were paid to bring this image up to a high standard, there are lots of things that could be improved, however, from Hershey's initial description, it sounded like the main purpose of it was simply to show his friend the sorts of things that could be done with PS, not to prepare it for publication in National Geo, or to be hung in a high end gallery. Accordingly, if I want to make a suggestion on such an image, it wouldn't be to criticize what appear to be JPG compression artifacts left over from the likely high compression / noise reduction baked into the image by the camera, but aspects of the image that might catch the eye of a casual viewer (ie, viewing it at the posted size). In this case, I felt that a gentle suggestion about composition or other global aspects would likely be more helpful.
Just my$0.02,
Tom M