Starting about 2 weeks ago, after conversations with three different members here about exactly this problem, I put together my own list of criteria/standards by which I would judge the challenges. It was not my intention to make this public, but since the issue as been brought out into the open, I have decided I will.
This may not be for everyone, but I do think it's a fair and balanced view of how any competition in cartography could be judged.
CHICK'S CRITERIA
Map: The map must be a map, not just a pretty picture. Depending on the challenge basis, the map should have clear indications of location and/or compass directions, identifiers of locations within the map, and depict something that requires navigation through the area by the map user.
Completeness: The map must be complete, finished, and ready to use as a navigational aid. Challenges are timed events and unfinished maps, no matter how attractive, should never qualify for votes.
Theme: The map satisfies the description of the challenge, clearly meeting all the criteria posted as the basis of the challenge.
Artistry: The map must be attractive, easy to read, understandable, with harmonious coloring if colored or well-shaded if greyscale. The elements of the map should fit together well, with matching and appropriate styles and textures.
Layout: The map elements should be laid out neatly in a way that draws the viewer/user's eye to the parts that are most important. Peripheral sections should be connected to their location or purpose in the main part of the map. Neatlines, borders, legends, compasses and other decorative elements should be in places that are useful but don't detract from the main map.
Content: The map should be rich with details, showing not just the main locations, but giving the viewer a sense of being in a real place with lots of variety and depth.
Challenge: The map should be and show advancement of the cartographer's skills. If it is similar to a map that the person has previously done, it was not a challenge.