The songwriting is brilliant (though Stewart has mentioned it is not among his personal favorites among his recordings) and there are lines with sheer beauty, like the opening of the second verse: "She comes out of the sun in a silk dress running like a watercolor in the rain." I also enjoy the seamless solos in the instrumental break, which morph from cello to acoustic guitar to electric guitar to saxophone.
In addition, the musicianship in the song is impeccable. I especially enjoyed hearing George Ford's bass work in the digitized version of the song, an element of "Year of the Cat" that unfortunately became washed out on the tinny AM transistor clock radio I owned in the 1970s.
Six minutes of sonic joy: what more could you ask from a musician?