Slaaaay...
Here's the list
STARĀ - Incredible technical proficiency marked by performance consistency and intonation accuracy as well as great musicality. The golden standard.
Aretha Franklin
Beyonce
Mariah Carey
Michael Jackson
So Hyang
Whitney Houston
A Listers: Good to great technical proficiency marked by generally consistent performances and solid intonation accuracy, as well as good to great musicality. Minor flaws.
A
Brendon Urie
Lady Gaga
P!nk