The Moultries that use the 6V battery are the models they used prior to 2007. And I agree - they were junk. However in 2007, moultrie changed all their cameras to six D batteries which substantially increased the amount of time the batteries lasted
I have 2 of the Moultries with the D batteries and love em. You want alot of time? Buy a 6 volt motorcycle battery or a 6 volt battery for kids cars and hook one of them up to your camera. That'll last.
I have 3 Moultries and I haven't spent over $150 on any of them. IMO they do just the same as the high dollar ones, but I still have that money in my pocket.