Going by WAR and a number of other things.
Hudson was great for Atlanta, but he was pitching towards the end of his career. Millwood still had many strong years after he was traded by us.
Hudson in Atlanta had 1573 IP 3.56 ERA 115 ERA+ 3.88 FIP.
Millwood in atlanta had 1004 IP 3.73 ERA 117 ERA+ 3.74 FIP