Too bad Price's video is in such poor sound. Her voice sounds very fluttery as recorded - this is one of her signature roles and, in the house, it was a miraculous sound.
Milanov, as usual displays her voice for all to hear; she sounds ideal for the part and gives us wonderful pianissimi, but it all sounds mechanical.
I was surprised at how dark Caballe's voice sounds here and as usual, she overdoes the pianissimo effects; whenever the line gets too difficult, she resorts to a pianissimo. They're gorgeous, of course. Elsewhere she slithers in some of the more florid passages, manages to fake trills and invent a meandering cadenza (at least one I haven't heard).
Ponselle starts with a gorgeous voice, sings everything practically perfect in every way but, to my mind rather mechanically. She finds a note she likes and seems to extends its value ( 2:31). Great trills. I really don't like the way she sings high notes, whitely and non-propulsively.
Pacetti doesn't belong in this company. No trills, sketchy coloratura and a voice that is of a smaller caliber than necessary.
I'm not sure who to vote for yet.
P.S. Update: I finally voted for Ponselle, though I find her version lacking; the others have more deficit points for various reasons. Zinka a close second - she did, after all, sing the role frequently at the Metropolitan Opera; it was "her" role. I couldn't vote for Leontyne Price even though hers was a famous assumption: I hear all of the later faults in her vocalism and she doesn't grab me in this video.