Considering she was not even a studio singer she was amazing. While famous for The Girl from Ipanema, she had a lot of Bossa Nova hits. I read an article about her a few months back. The author said she lacked the range of other famous female singers of her time. She did not compare to say Elis Regina or a Vikki Carr. But there was something about her voice that's was so comfortable to listen to. She was like a smooth Bourbon after a long day or a hot cup of coffee on a cold morning. You just enjoyed listening to her sing much like Karen Carpenter.
Listening to her now. While I like Girl from Ipanema, I really like Tristeza, Meditation, It Might as Well be Spring and Corcovado. The last two were recorded with Stan Getz and Joao Gilberto.