Quality, stature, caliber are often interchangeable as indicating, when used without modifiers, distinctive merit or superiority.
Quality implies a complex of qualities (see QUALITY 1 ) and is therefore always singular in use. The term usually implies a high order of excellence, virtue, strength of character, or worth.
Stature implies that the one considered has reached or is in process of reaching the height or greatness possible to one of his kind.
Caliber suggests extent or range especially of one’s mind or powers; it may connote unusual but measurable range, scope, or breadth of ability or intellect but often depends on qualification to supply a standard of reference or comparison or to indicate the direction of deviation from the norm.