While much has been made of former model Cassie's leap into the R&B ring--the vampy, MySpace-fueled first single "Me & U" topped more than a few best-of-summer lists--almost as much has been made of the wispiness of her voice. But what those who have stopped straddling the fence know is that the pillow-lipped beauty makes up for what she lacks in vocal power with an abundance of less obvious musical proficiencies: Cassie's a master of sass, a guru of guile. Hear it not only on the mildly menacing and seriously thrilling "Me & U," but also on "Long Way 2 Go," a merciless tease aimed at an amorous man who really ought to have known better. The rest of this brief disc bumps along on the greatness of its beats. Master blaster and producer Ryan Leslie (also Cassie's beau, it's rumored) strings together a minicourse on sampling as he slyly dips from old-school jazz to disco to vintage flamenco. Credit Cassie, though, for concocting a whole lotta 'tude. R&B has a whispery new minx.