it sucks not only because of sustained dps on every boss (since it's burst isn't that much higher than destro on xaril, and on the pull my guild has to stop dpsing anyways to avoid letting parasites alive on the room) but because it lacks the power to self heal destro has, ember tap is gg when your getting fiery edge
but when you have the boss on farm, and shit starts do die faster and your healers can handle fiery edge without you needing to embertap twice, then affliction starts to be more appealing.