It may depend on how you like to clean your cages. Back to Back the Brisbane cages would NOT fit through a doorway to be taken out of the room you have the cage in - or out most doors (other than sliding doors) to take the cage outside for a good hose down scrubbing and thorough rinse.
If you clean your cage outside - the Congo cage might be a better choice for the ease of moving it when necessary.
If I ever need to replace my current large cages the Congo will be my first choice - about 12 inches taller than my current colony cages.