Originally Posted by
Akainakali
It's mostly a question of what is the other gear you have, that they'd be replacing.
Spehuz's is actually very strong if it's a fight (AOE or Single target) with any opportunities for interrupting/CCs. So that's the only one that offers any direct DPS boost.
None of your other legendaries offer any specific boosts for single target, so it's mostly a question of how much are the stats worth, vs what is on the item they'd be replacing. That tends to favor items with a large stat budget like Helm, Chest, Legs. It may well be that the increased/additional stats (non-DPS legendaries have 3 secondary stats vs 2 for most items) might trump the Sephuz's proc bonus, depending on what they would be replacing.
The Voodoo Mask can be a significant aid to survivability, especially on progression and might be worth taking on that basis. The healing from the legs in combat, is not generally strong enough to be worth it on that basis alone, especially on any movement intensive fights.