Functionally, not much.
Aesthetically: better QC, paint, finish, parts plating, saddle, grips and name badge.

Check the spoke count for re-build. 32H FR, 40H RR was the earlier spec but that changed in some "boom era" bikes.
An AW w/ the metal oil flip-cap is way cooler than plastic, bring a magnet as the Humber may have the very desirable alloy hub shell.
Check the brakes for the proprietary fixed cable ends, you can mfg a workable substitute but they are rare & expensive and a fiddle to work with.
Does either have a proper Brooks B-72/66 leather saddle?

-Bandera