I have gone back and forth on this trying to see a difference between OTA and Sat. On my 48" LG close up, I may see a slight difference, with OTA being sharper, but I stress, may. From regular sitting distance, I do not think I can see a difference. Neither can I say one channel/network is consistently better or worse. It seems to be by what show it is. I consistently think NCIS looks soft. But Blue Bloods, on the same network looks good. The ABC shows "The Middle" and "Modern Family" look quite sharp, yet "Big Bang Theory" not so sharp. The late night shows except Conan always look very sharp.
As for 1080I or 720P, again on my TV, very little if any difference, though just like the experts say, fast moving objects may look a little better in 720P, but not night and day. And very close to the TV I do think I can see a slight difference in people's faces, with 1080I appearing possibly sharper. But if I were to come into the room and someone else made the settings I am not 100% sure I could see the difference from a regular sitting distance.