Wave Breaker vs SoS and a shield

[Nerfix]

Let's say that the unit is a big one and he has a Robe of Shadows, Amulet of Luck and the Bracers. He can also cast Astral Shield and Astral Weapon. These are by no means final equipment but are easy to make. He can also cast Quicken self but I haven't researched it yet. He has somewhat high base def thanks to several picks in Water magic.

Which one of the weapons would you pick? WB gives you three attack per rounds while Sword of Swiftness gives 2 attacks and leaves a slot free for a shield. Other options include Frost Brand, Fire Brand (found one!) or perhaps a sassy Glaive of Doom.

EDIT: I should say that my choice of shield is pretty restriced. Lucky Coin or Black Steel Kite Shield...