Skull of Dire Ahamkara

Excerpt from "'Should I Buy It?' - Ice Breaker & Other Exotics" (Mar. 6th, 2015)

Skull of Dire Ahamkara is one of four Warlock helmets, along with Apotheosis Veil (Any), Light Beyond Nemesis (Any) and Obsidian Mind (Voidwalker). SoDA features dramatic damage-reduction during your Super, and decreases your grenade cooldown by an extra ~2 seconds when Energy Drain is triggered.

SoDA essentially grants you class talent The Hunger, extending the Energy Drain effect by 3s; from 5 seconds to 8 seconds. That translates to an extra -1.8 seconds off your grenade cooldown (from -3s to -4.8s). Even paired with the reduced damage, it's underwhelming. Most Voidwalkers seem to prefer Obsidian Mind if they have the choice.