Wings of Rage deals more damage than Spear of Light if you include the damage that follows the initial attack. The skill is much weaker than Spear of God but ignores passive defense, defense and protection. That makes it very useful.
I think I'd probably finish maxing Neamhain, then switch to Morrighan for day-to-day use. When I want extreme overkill damage, I grab my Brionac, some shock crystals, and switch to Neamhain.