I am not defending NGC's grading on this coin. The big brown spot does effect the eye appeal part of the grade, but eye appeal is only part of the grading criteria. NGC may have deducted something from the grade to arrive at MS66. The coin may technically be a MS66, but this is the type of coin most buyers will stay clear of because of the brown spot, so the coin's value will decrease. This coin also has white spots that may have came from dipping when someone tried to remove the brown spot.