I would have to say that it's exactly like fighting with a two handed blue sword, just weigh a little more...and not have to worry about hitting with a flat.
I just built a 2 handed barrel mace, 8 feet long It is so bad *! If I can get 2 compotent shield men I think I can do some damage to a shield wall. but I maight as weel paint a bulls eye on my forehead for the archers.