My ramp has all the extra Blender types of HSV colors which is different than the RGB mode.  RGB is a linear change so that Red 255,0,0 goes to Green 0,255,0 but in RGB mode at the 50% point it is a muted yellow color 128,128,0, whereas in HSV it is Red 0/240 Hue and Green 80 then Yellow would be 40 but at the same saturation so remain vivid instead of muted.  Really depends on what you are trying to do. 

Poser 5, 6, 7, 8, Poser Pro 9 (2012), 10 (2014), 11, 12, 13, 14