I tested the AA size Amazon brand battery to find out the actual usable capacity as compared to the AA Duracell Procell battery. The results showed that the Amazon battery is about 88 percent the capacity of the Duracell. If you calculate the cost per unit capacity, the batteries are almost identical. The Amazon battery was actually slightly more expensive when represented in cost per Watt-Hour. Because of this I would probably choose the Procell (if I can get a good price on it) just because it means less frequent battery changes. The Amazon battery is a surprisingly good battery though. You will probably barely notice the difference in capacity, so if you don't want to waste time shopping around then its a good choice.