She has an amazing voice. She experiments with what the instrument of the human voice can do, and her experiments are not always that successful - I really, really struggle with 50 Words For Snow, for instance.
But even on that album there are some tracks that are instantly arresting and haunting. She adds narrative to her voice using very few words, and that is a rare talent.
I can think of lots of songs where she does not screech at all, beyond The Man with The Child In His Eyes which everyone seems to quote.
From The Red Shoes: These Moments of Pleasure
From Aerial - A Sea of Honey: Joanni (easily the best song ever written about Joan of Arc), How To Be Invisible, A Coral Room.
And then all of A Sky of Honey, best concept album since The Dreaming
From The Sensual World - This Woman's Work, The Fog, The Sensual World, Love and Anger, Never be Mine, Walk Straight Down the Middle
I could go on and on and on. Anyone who dismisses Kate Bush as a screechy prancey poser is suffering from cloth ears.