You may not know it, but before he forayed into crooning "This Masquerade" and light-weight stuff like "Breezin'". George PLAYED HIS BUTT OFF
For Proof, check out "The Cooker", "Willow Weep for Me", and several others. Kind of like a less subtle Wes wailin' upside your head. Awesome technic, killer lines, I dig the organ and the Bari Sax stuff....
He does sing, but except for "Summertime", it is not smooth-jazz sounding.