Here's my two cents on him:
P4P top 3 due to possessing the world's best resume.
his prime years ran from 1918-1925 by my estimation and in this time he fought the following:
HW - Miske, Smith, Moha, Brennan (x4), Meehan (x2), J Smith, Renault (x2), Weinert, H Smith,
LHW - Levinsky (x3), Dillon, Tunney, Miske, Houck (x2), T Gibbons (x2), M Gibbons, Loughran (x3), Flowers, Rosenbloom, - Tunney (Dx2)*, Loughran (Dx2)*, Z Kid (D) - Gibbons (L), Tunney (Lx2) .
MW: - Dillon, Walker, Slattery, Chip (x2), Moha, Wilson (x2), Brennan (x3), McCoy, J Smith (x2), Downey, Moore, - Flowers (D)* - Flowers (L) O'Dowd (L)
and many more that I could list. the fights with an * are because reports indicate the official decision was controversial.
In my opinion he spent a total of 97 months as the best fighter in a given division (61 months over 2 stints at LHW and 38 over 1 stint at MW)
At LHW whilst on top he faced 17 opponents that I deem to be noteworthy.
At MW whilst on top he faced 5 opponents that I deem to be noteworthy.
That's a total of 22 opponents faced whilst defending his claim as the premiere fighter in a given division.
For a few months he simultaneously ruled the MW and LHW division and during his prime he defeated every man he faced.
Also, for what it's worth, he's the one notable white HW contender that Jack Dempsey didn't face during his career.
A truly legendary fighter and it's a crying shame that we don't have footage of him at his best.