Fiery Aura with Shadow Meld probably has the edge on Shield in survivability since it also has a shortish recharge heal and the higher resists. Fire can do more damage over a longer time than Shield since Burn can be activated over 6 times as much (very high recharge) as Shield Charge. I'm not sure if you get the bonus from AAO for SC if you use it outside of a mob, and if not, that is some substantial damage lost and you'll be forced to possibly lose some of the mitigation the knockdown gives for the extra damage. The final nail in the coffin is SC is smashing damage vs. Burn's fire.
There are some exceptions for shield however: Shield is going to have the upper hand against enemies that debuff your defense; Shield also has generous resists, and a damage debuff that further fortifies damage mitigation, can softcap ranged or melee def. quite easily, lastly comes with +max hp which allows you to invest IO's more heavily in other areas; AAO is always up and will give substantially higher single target DPS than /fire.
I'm trying to figure out which one to go with for pure DPS and survivability.
Shield has shield charge. And AAO. However, I plan on taking Shadowmeld...which will give me some ridiculously awesome survivability with the resists, especially because I plan on doing a high recharge build.
So I guess the question is, should I go with shield charge, or go with the Fiery Embrace+Burn combo?