As of February:
25 mile radius
Quality Course = 5 reviews min, 4.00 min
78738, Austin, 34 courses, 7 quality
28202, Charlotte, 34 courses, 5 quality
76011, Dallas, 35 courses, 4 quality
97045, Portland, 26 courses, 4 quality
45203, Cincinnati, 28 courses, 3 quality
55313, Minneapolis-ish, 28 courses, 3 quality
50323, Des Moines, 22 courses, 3 quality
80433, Denver, 18 courses, 3 quality
18052, Allentown, 18 courses, 3 quality
46341, N Indiana, 9 courses, 3 quality
54846, Highbridge, 9 courses, 3 quality
15086, Pittsburgh-ish, 7 courses, 3 quality
64129, Kansas City, 17 courses, 2 quality
55408, Minneapolis, 40 courses, 1 quality
http://www.dgcoursereview.com/forums/showthread.php?t=12004&page=11