I play eldar (shame on your dark kin!) and one of my opponent plays dark eldar.
The unit I fear the most is a wich archon with agonizer and pistol and drugs, with his retinue of 7 wiches (with wych weapons) including of course an leader with agonizer, mounted in a raider.
In one battle they destroyed:
-10 swooping hawks that they charged
-10 stricking scorpions, tooled up, that charged them
-the avatar, that charged them
And they finally FLED!(3 of them and the lord), after having been assaulted by a tooled up 10 scorpions squad (and having killed 6 of them)
So in a 1.5k game, they destroyed 634 points of Eldar, while they were worth around 230 pts.
And then I promised myself to never charge wyches again...