In re-reading my post, I think I should have elaborated a bit more about Sfraga's style. As those who have read my posts about jazz during the past 3+ years will know, I have a strong preference for TRUE jazz singers, rather than the "jazz crooners" who have become popular in the past few years (I include both Barber and Krall in this category -- they're fine singers, just not true jazz singers).
Sfraga is closer to being a true jazz singer. She takes more risk and comes closer to making the song her own, rather than just singing the words. Her voice has a nice range, although I'd probably like it a bit more if it had a bit of darkness to it. If she continues to record, her lower range will probably get fuller, which will be to her benefit. Sfraga reminds me a bit of some of the better women singers with the big bands of the 1940's, such as Dakota Station, June Christy, and others.
For those who like female jazz vocalists that sing with a style similar to Sfraga's, you might also enjoy the work of the following artists: Karen Krall (who did a terrific album with Dexter Gordon in the late 1970's or early 1980's); Sheila Jordan; Morgana King; and DeeDee Bridgewater. (I have deliberately not mentioned the greatest of the women jazz singers, such as Sarah Vaughn, Carmen McRae, Ella Fitzgerald, Ernestine Anderson, Betty Carter, and others who are in a pantheon all their own.)