Yes, that was a stunning delivery. Though it is my best estimation that a choir with more subtle qualities would have made the job a bit easier for Elvis.
In case of a choir with forced vibrato (or should I say tremolo) it is harder for the solo-artist to put subtle contrasts in the song. The Sweet Inspirations have also made this mistake quite often - I'd rather hear the Jordanaires, the Imperials or the Stamps.
Others start out rough, but just like fine wine, improve with age. For example: it's the difference between Elvis' breakthrough and the early 60's. There are ballads in the early years, but Elvis had begun to develop more subtle qualities in the early 60's. ('It's Now Or Never', 'Are You Lonesome Tonight', 'Surrender')..
He then cleansed his soul in the late 60's and once again returned to more romantic & dramatic material in the 70's.
My favourite vocal performances are 'Hurt' from his last concert and 'Unchained Melody' from 'Unchained Elvis' (May, 1977)..