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.
Billie or Ella? Maria or Renata? Technique or feeling?
I stand back to no one in my admiration for Ella Fitzgerald's technique but all the vocal fireworks make for precious little emotion. Billie Holiday on the other hand makes you feel she's singing just for you.
Technique vs emotion also goes in listening to Renata Tebaldi (superb technique) and Maria Callas who like Lady Day makes you feel she's singing just for you.
David Oistrakh was a violinist who combined flawless technique with raw emotion. Sviatoslav Richter was his counterpart on piano. Their modern day successors are Julia Fischer on violin and Daniil Trifonov on piano.