Why not use both? Sweeping wind is fire and forget aura that stays up as long you keep beating enemies. 60% damage per cycle is massive damage bonus. This comparison is so artificial that i don't even get it. Sweeping wind is background ability that doesn't overlap with anything else you do. Cast it once and it keeps constantly churning damage while you are doing other **** with another abilities.
If it's long fight one cast can net you anything from 60% weapon damage to pretty much infinity. Key terms here are damage over time, fire and forget, infinite duration. The longer the fight the better sweeping wind is.