We can rate the band AND the singers of that band? I can understand the singer part, but the band part is part of another thread somewhere. I'll just do singers.
ZP Theart, the man with 4 octaves of range in notes from DragonForce. Judge him by his talent and experience, not by the band in general.
And I'll rate Cream with 7.3/10 . Cream is pretty good for me, I just like a bit of metal to go with it.