She's on record about never feeling comfortable with how she had to pitch her voice on those early RAK/Mickie Most/Chinn-Chapman hits, she felt it sounded samey and lacked expression. As early as the later 70ies she tried to escape that.
No one would mistake Suzi for Aretha Franklin, but when she doesn't have to squeal, she has a real nice tone - to me:
I'm actually gonna see her on that coming tour.