Top notch production, song writing, and execution, but I would ask you to pay special attention to the lead vocals by Gladys Knight, at high volume. She shows a full range of power, emotion, richness and texture, with subtlety and tenderness, that for me is simply one of the greatest vocal performances in popular music history.
She not only has a great voice, she knows exactly how to use it, which is really what separates great singers from the pack.
Listen once, twice, three times on a loop, and see if you don’t agree.