both Joss and Beyonce have them..

from my perspective...Beyonce has a lot more power and control over her voice....her voice is more mature and her soul comes across as more natural than Joss....

Joss is good, but her voice still sounds a bit like a young girl who is riffing to make it sound like she's got soul....B' is a woman who can blow....period. On record she doesn't show it as much ...but live it's right there for you.