I never bought into the no parralax claim because I shoot steel at 300 yard much better with my irons flipped up and cowitness with my eotech than shooting with the eotech alone. I still love my eotechs because they just feel natural shooting with both eyes open and acquire targets extremely fast. I've shot many armadillos and other critters on the move from the back of a moving Kawasaki mule in the dark and nothing performs quite like an eotech in that situation.