We have done both and enjoyed both options. Had an 8:10 one morning for a 9:00 park opening, so we were able to get in and out of breakfast pretty quickly, even with the character visits and a second trip to the buffet, and then walk over to the Safari and be one of the first ones on the ride with no wait. We have also done something around 10:40 and taken advantage of the "brunch" effect -- i.e., early enough to catch the breakfast buffet, but late enough that by the time we finished our breakfast trip down the line, they had put the lunch options out so we were able to enjoy that, too.
At this point in the life of DAK, I'm not sure that early morning photos are a high benefit -- lots of construction walls, etc., are up. In a year or two, that may be a whole different story, but for now, I'd say early breakfast might simply get you to the back of the park earlier, while late breakfast has the "brunch" option. Just go with whichever sounds more appealing. My personal preference is to hit the park at rope drop, enjoy a couple of hours in the park and then take a break for a nice meal.