Curious what is the best gladiator/merciless OH together with MH mace for a sub rogue.

Am I right thinking that the 1.40 speed dagger is slightly better OH than the 1.50 speed mace/fist/sword?

I'm asking because I see so many rogues with 2x Mace/Swords, maybe they buy it for looks or potential combat specc with weapon specialization, maybe the difference in dps is so slight it rarely makes a difference? Or is the Mace/Sword better?