Sorry if this is a repeat question, but I was unable to find a post on it.
As an affliction lock (41/0/20) that primarily uses shadow spells, I don't quite get how an item with +Shadow is better than one with the same amount of +Spell Damage. It would seem to me that whenever I use a fire spell, that I am just missing out on that damage.
So, as an example, is a Tome with +40 Shadow Damage better for me than a Tome with +40 Spell Damage? Or does +shadow only help where it is X% higher than a similar Spell Damage item?
Thanks for your help on this noobish question.