sgtsches
I'm not quite sure about it, but it allows you to mount weapons and thrusters on all six sides, and is better than a cube because they don't have hull stresses that are focused at the edges while spheres have none, which allow stresses to be evenly distributed around the hull, and is also good at holding in atmospheres...
Of course i haven't really invested much of my time into this, but maybe you could do more research to see what a good design would be. What would the best realistic hull configuration be?