Like Deathly Chill, beware of relying too heavily on this skill as a primary source of damage. Though effective initially, once your foe's health becomes lower, this skill becomes far less useful.
Because this skill deals a large amount of armor-ignoring damage, especially to healthy targets, many Necromancers find it primarily useful as a spike skill. If spike damage is not particularly desired, consider Vampiric Gaze with its lower cast and recharge times instead.