There never has been, nor will there ever be, anyone to compare to "Nina Simone"; she is in a category of "One".
In the beginning, I heard her artistic merit, and her virtuoso on piano; in the end, she conquered with raw power; her voice grabbed, and held you in it's vice.
https://www.youtube.com/watch?v=Ow6fQbpUli4
https://www.youtube.com/watch?v=4PMriloy62o
A song has a life of it's own, the same as any human being; that is, if you can hear into the song and really know what it's about; this song is about; "It ain't over until I say it's over, cause I put a spell on you"
This is three different versions of the same song, and I can hear the essence of the song on all three different versions.
https://www.youtube.com/watch?v=a1AE_bCoPSI
In that second version by Nina, the guy on guitar nails the spirit of the song. Since it's "Screaming Jay Hawkins" song, he can do whatever he wants to.