Yeah I'm not keen on having any light apart from white inside a rig as white nicely highlights your interior whereas coloured lights bleach everything out.
White light with coloured coolant looks the bees knees IMO
But with rgb you get to choose a shade of white light that looks best with everything else. I've found certain shades of white can have a large impact on how the fluid looks. A certain shade of white will make red fluid "pop" quite a bit.