Is Xiao or Childe Better?

Lore wise, Xiao would win, even though Childe is still incredibly powerful, not because Xiao is an adeptus or god like, but because killing is his life skill, and Xiao has more experience, and more strength than Childe does. Xiao wins this fight, every time.

Is Childe better as support or DPS?

Childe Best Teammates

Childe is the Main DPS, so focusing on his damage output is key. Unfortunately, his Elemental Skill cooldown is high, so having other damage dealers in the party is a must.

Is Xiao a good character?

Xiao is a 5-star Anemo Polearm character, adept at dealing huge amounts of AoE damage from Plunging Attacks. He is widely regarded as a great and balanced character, who excels in AoE but somehow falters in the single target department.