I thought I'd chime in about what is my favorite troop option the Eldar have. Notwithstanding their super cool hats, I have used them for many years to great effect. They've had editions where the weren't all that great (cough cough 3rd cough cough), but once they finally received better range than guardians, their usefulness multiplied exponentially. This was especially true in editions with fixed AP, as heavy bolters would outright ignore guardian saves, but DA's could still make a full attempt.
While 8th edition has certainly opened up some solid options for guardians, especially with their improved BS and ability to get an invulnerable save via strategems, I still find dire avengers to be my bread and butter troop option. They can bring a solid weight of fire from outside rapid fire range and can really close the distance with their ability to advance and fire without penalty. The rending ability of the weapon also pairs well with doom, and I have slain numerous tough targets in a hail of shuriken fire thanks to this combo.
They truly shined in a league game I had the other day in which I claimed an objective in my opponents deployment zone on turn 5 from about 30" away, using matchless agility, quicken, and fire and fade to seal the win.