Orichalcum Sword

Ore swords in Hardmode sit in an awkward spot. By the time you can smelt this you are usually not far from a Hallowed blade or a boss drop that outclasses anything craftable from raw bars, and those same bars are what you need for armor and the next pickaxe. Armor first, always. If there is metal left over, the sword is a fine gap filler for clearing the underground hallow and the evil biome while you hunt for mechanical boss parts.

There is no real decision between this and the Mythril version, since a world only generates one of the two ores. Autoswing means you can hold the button down and walk into a group, which is most of what a mid tier broadsword is for.