Laetum is absurdly strong. It doesn't proc slash, but it has such a high damage output, it doesn't need to.
Phenmor is the opposite. A bit weaker, but massive amount of slash procs make it kill just as fast, if not faster.
Praedos are really boring. But they are a Tonfa weapon with average stats, so that automatically makes them good.
Hespar is apparently a bit weak, but I can't confirm that since DE had the genius idea to make the Blade a C rotation reward with 10% chance on a gamemode that needs 25 minutes for 1 C rotation.
Havn't used Stahlta Nr3 yet either.