I've used some of the others, mainly the fire/cold damage ones, since they let you deal potentially large bonus damage to certain enemies. Or at least I think they do...
The issue I have, is that the same spells that increase your fire damage, also increase your fire resist. But most enemies that DEAL fire damage also RESIST it. So very rarely do I feel like it's going to be awesome.. and then the massive penalty to init kicks in
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