Both the front of the car and the base of the windshield are high pressure areas, so it depends on how you want to draw the air in to determine which is best. Neither has a distinct advantage. A cowl hood (ala GM) is necessary for the windshield area. An isolated air cleaner with ram air tubes would be required for the front of the car, which requires a certain amount of under-hood space and radiator core support room to be effective.
The low pressure area is over the center of the hood. To be an effective scoop in this area requires a fair amount of height, which is how the snorkel scoop came in to being. The factory style AAR, Shaker, or the '69 Air Grabber versions are somewhat effective in that they do pull cooler outside air compared to heated engine bay air, but they do not get a ram effect like the taller version like the TA, WO/RO, Popup Air Grabber, or Six Pak scoops.
