What I look for in a voice is for it to be unique. I don't really care if a singer sings well. Really, it's about emotion, or being able to sing the lyrics and actually mean it. A lot of singers sing good notes but forget about what words they use.
ZeddA DJ can't just play one song. It's about playing a set, or how you connect songs in those two hours, and where you place them.
Zedd