Hands down Belladonna. I don't need to state the obvious. Hatfield lost any youthful aggression to his singing years ago. Tom is Tom. His shouting style is great with Slayer but that can have it's limitations. And Mustaine was probably never a natural born singer. Great guitarist but whatever his voice is shot now. Last time I saw him, he was singing falsetto and sounding like a muppet or a cat in heat.