Billie or Ella? Maria or Renata? Technique or feeling?

Both are great but Callas was a better actress. Given her life story, she had to be.

There's a great line in the comments section by Larry Mitchell,

"Tebaldi songs with a gorgeous voice.  Callas speaks to the gods."

@stuartk You do realize that you're describing your subjective experience here as though it were objective, right?  

You do realize you're not me so how do you know my subjective experience isn't objective, right?

@stuartk I've played CDs that I find very emotive for friends, only to witness them sitting  impassively.

You need better friends. I kid. I kid.

Anecdotally, I had the opposite experience playing a semi bombastic recording to a friend who rocketed out of his chair exclaiming Wow! That's the kind of full orchestral music I love! I was taken aback at the extent of his enthusiasm albeit gratified that he liked the recording so much (Kyung Hwa Chung playing Prokofiev's Violin Concertos).

@stuartk I'm guessing there are many fans of guitar shredders who'll assert they experience intense emotion from listening to their idols' gymnastics.

I have heard that proposition from fans of the violinist Jascha Heifetz who had superhuman technique. With age, I can meet them halfway. e.g. Heifetz/Reiner in the Tchaikovsky Violin Concerto. Nice nod to Mr. Buchanan. 

This technique vs feeling carries over into other walks of life. My chess hero Tal was known as the Magician from Riga. He would make one spectacular sacrifice after another until finally he somehow had his opponent cornered. His opposite was the calculating Keres but sometimes they'd jump into each others territory and Keres would play with flair while Tal became all neat and tidy.

I have to mention Ayrton Senna in F1 and his nominal teammate Alain Prost. There is a famous clip of Senna at Donnington in the rain coming from fifth place to pass the greats of his day as if they were standing still to take the lead. All before the first lap was over! 

Back to hifi. If you take the line that all is subjective to its logical end, what are we even doing here? Does it mean anything when someone says that a particular piece of equipment transported him to musical nirvana? We can cloak our opinions  in objective sounding language like the midrange was superb or I could really see the images of the instruments but it's all subjective is it not? Only if we accept that there is value in the subjective is there any point to a forum like Audiogon. 

@stuartk Otis Rush and Roy Buchanan!  Great guitar player mentions!

If we were trying to reach the most legitimate, objectively, empirically-based rankings of certain performers, technical proficiency would have to be taken into consideration.  To stay on the topic of guitar players, while I would never personally (subjectively) prefer, say, Yngwie Malmsteen and Eddie Van Halen to, say, David Lindley or Jesse Ed Davis, I would have to rank Yngwie and Eddie higher. They’re just too good, and their disagreeable music is not enough to trump their obviously superior technical proficiency.

Excellent post, stuartk. You wrote much of what I was about to write. You are exactly correct re the role of listener bias. For me an even more interesting question is why, when considering artists in the admittedly very small group at the very top level of excellence, some listeners feel the need to declare one or the other “the best” as if that opinion is some sort of objective truth. It is instead, and as you point out, at least in part a reflection of the listener’s bias. Moreover, to not keep a more open mind to this reality doesn’t enhance one’s acumen as a listener; it limits it instead.

I couldn't say anything about the ladies mentioned due to lack of familiarity. But as to the difference between "Technique or feeling?" I'll vote for feeling. Computers/synthesizers/drum machines may do things with precision, but will never replace the human element needed to relay expression.