I love both, but the Relic Blade was an instant fave of mine. Its not op, but it is an amazing weapon.
The DS is lovely especially if you enjoyed Saltys Rapier but it is a bit op imo.
Also… inb4 Force Greatsword threads talking about how op it is and that it ruins the game. You can shoot thru the level and with the brainburst on hit, you regularly pop heads in the next room etc.