[Ashara or Xalek for Darkness spec?]

I use Ashara over Xalek, even tho Xalek has all my dps gear from raiding(which is almost every slow) Ashara seems to beat **** down way faster and she's still in crap gear(she has 4epics atm). I kept her gear up leveling and only had to change her our to solo 2+ heroics or 2man 4heroics with a friend.