I keep both black pines and indigos and both species can empty out a room quickly when they defecate! Ironocally, those are my cleanest cages. They get cleaned as soon as I enter the snake room and inhale that all-to-familiar smell.
Both species are great snakes. Indigos seem a little more aware of their surroundings. Both hiss and bluff (especially pines)and both can be a handfull when they want to move. Black pines try to escape by moving backwards in your hands; indigos try to escape by moving forwards in your hands. Believe it or not, there was a time when black pines were more pricey than indigos!