CIEXYZ (CIE 1931) had the best brightness axis ever. But the hunt for the best color-axis seems to be ongoing. CIE 1960, CIE 1964, CIELAB/CIELUV 1976... CIECA

CIEXYZ (CIE 1931) had the best brightness axis ever. But the hunt for the best color-axis seems to be ongoing. CIE 1960, CIE 1964, CIELAB/CIELUV 1976... CIECAM02 CIECAM16 seem to be new iterations. Maybe those are good now?