Judd is the clear stand out, Entire game is based around aggression and getting the ball in contested situations. Ultimate professional footballer.
Cousins is a champion and works harder than anybody at the club to improve his game, good in traffic and is courageous as they come.
Kerr is really really good, somebody from outside the club could argue that he is the best of the 3 but the fact is that he is injury prone, an inconsistent kick, not reliable around goals, can be unaccountable, doesn't work as hard off the track and doesn't do well when copping a tag, much lower overall work rate than the other 2.
Judd > Cousins > Kerr