What's the difference between Elsa and the Snow Queen?

I think the idea was to feature both the Snow Queen Disney created, Elsa, good but having trouble controlling her powers, and the Snow Queen we are used to seeing in literature: just plain coldblooded; the one who purposefully froze people to death, created ice zombie-like creatures and put a shard of ice (or mirror) in your eye and it made your heart freeze and your brain crystallize in a sociopathic machine. So the main difference I think is exactly that one is good and the other is evil: they are both faces of the same character so they have more or less the same powers, both are queens and so on, we (or if it's online somewhere I haven't yet been able to find it) don't yet have the background Kitsis and Horowitz will give the Snow Queen, but I do hope they give her something cool - pun intended ^.^