Are Dark Eldar good?
How good are Dark Eldar in 8th? AFAIK, Dark Eldar are strong this edition as absolute glass cannons. They strike fast and hard but crumple like paper. As such, they're a potent faction that takes some skill to use.
Why are Eldar and Dark Eldar allies?
Eldar and Dark Eldar Allies? They resent eachother and think of eachother as fools but they both have the prime goal of the survival of their race and the reinstatement of the Eldar Empire as the prime force in the Galaxy.
Does Eldar fight Dark Eldar?
The Eldar suffer somewhat particular from this comparison though because the most direct analog to them in Warhammer Fantasy is the High and Dark Elves, who are defined by their animosity to one another. They hate each other, and are often cast as two opposing sides.
Are Eldar good in 8th edition?
Mechanized Eldar is still good in 8th edition, but in 8th Edition there are other tools available and Eldar naval fleets of Wave Serpents, Falcons and Fire Prisms are neither required to compete or necessarily optimal. Looking at your army in particular, you have a lot of the tools you need to make a very good list.