I did a comparison yesterday between NBC Columbus and NBC New York during the afternoon hockey game and there was no contest. NBC Columus was bright, sharp, crisp  and clean while the NY feed (channel 82) was dull, less colorful, less vibrant and seemingly muted. We really have been screwed by Direct's manipulation of the HD signal. I cannot measure the resolution of the HD l get for the Columbus HD locals, but I am pretty sure that I was seeing the difference in 1920x1080 versus 1280x1080 and the bandwisths constraints thereof.
Whenever I do comparisons of the 720p stations (Fox and ABC) I really do not see much difference, primarily because Direct is not altering those resolutions.