I added the Standard Poser Version of the Color Ramp they have as a comparison.  With the 3 input Color Ramp you can have a sharp cut as the input value gets to a specific value or like Blender you can have it blend between the two colors.  Also the 3 input allwos you to change the point where a color value comes into play.

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