Medium percussive weapons:
+1 to hit opponents with AC 16 or more. Otherwise, -1 to hit.
Certainly a mace would fuck you up. No doubt about it. But a mace can only kill you outright by hitting the head or the spine, whereas a sword can do terminal harm in all sorts of wonderful and exciting ways.
Other interesting things about maces: they have been used as a symbol of secular power around the world throughout history. Something about a bloody great club just screams I'm in charge. The particular mace pictured above is in fact so important that the House of Commons isn't considered in session unless that mace is there. It represents the royal authority and can be lost just by picking it up and moving it.
See those things police carry? Maces. For hundreds of years keepers of the peace have carried maces of some sort or another. After all, it's peace they want, not bloodshed. Pull a sword and you're saying you're ready to kill someone, pull a mace and you're saying you might kill someone or maybe just make them wish they'd been a bit less rowdy.