Again can't comment on the Durecell, but run the standard Hahnel and have been utterly impressed by them (hitting the claimed 1200 battery shots with GPS, wifi & live view), and is recognised by both camera & charger fully. If I'd have known how good they were before I bought them I'd have only bought the one not two, as I don't actually need 3 batteries with this 6D. Used to run 6 with the 5Dmk1