42.5, just an old habit, doesn’t mean anything special When feeding a single channel into noise vector (like grey scale output from Object Info/Random), you need to increase distortion to get different colours out of the noise node. If left at zero, all three channels will be equal regardless of the noise scale value. But too low scale, and colour will only drift slightly as you observed. Those two values don’t change rendertime much (if any), whereas Detail will and have no impact for this so I leave it at 0.
Use Colour output if you want to have three different random values to play with. I used green as a means to drive the roughness value as an example, but could be anything. Like Hue Saturation Value with separate controls without using the colour ramp. I’m not really a fan of the colour ramp as it’s contents can’t be exposed to a user interface like values and colours can.
Use Fac output if you only need a single random value, although in case of Object Info/Random, the noise node would not be required - just plug the Object Info/Random straight into the colour ramp.
The contrast node is just to get more of the highs and lows rather than center distribution around 0.5. I’m not sure what you would need to do to get a perfect evenly distribution, but it’s good enough for my random desires