The Exotic Sword Does solar damage and even has a perk that helps speed up the recharge of your super. Some additional info about other perks are below.
Tempered Light Perk: Increased Armor when welding the sword. (Gives you the chance to get up close in the crucible)
Scabbard Perk: Increase Sword ammo capacity
Thrive by the sword Perk: Kills with the sword grant super energy.
Phoenix Uppercut Perk: use R2 to launch into a solar light uppercut. (YES!)
Warrior of Light Perk: Increase damage for your R2 attack.