Listen carefully to “Li’l Darlin'” both by the Count Basie Orchestra, and by Lambert, Hendricks and Ross with Joe Williams.  The first thing that struck me when I heard these two versions of the song, is that you almost have to listen twice to tell which is the instrumental and which is the vocal.  That’s how precise LH&R’s style and phrasing was!  Here they are side-by-side.  What do you think?