The Horseman's blade is objectively superior in terms of damage output. The spawned pumpkins are only limited by the number of mobs you can hit with it. If you wire a bunch of mob statues to 1 second timers, swinging on the mobs as they spawn, you can flood the screen with pumpkins, dealing enough damage to wipe out every boss, moon event, and invasion in the game. A Terra Blade, even with its superior tooltip DPS, doesn't compare. Nor does any other weapon currently in the game.