Great thread buddy. I remember the ultra green Congo. (Now, if we could just get that colour-changing mystery insert out of there... Lol)
It is short-sighted to call members of this club "haters" and I would surmise that those who do so are not competitive players. As RJW alluded to, you are choosing aesthetics over playability when you use colour GI (and/or incorrect flipper bats).
It is particularly annoying in the competitive environment. Playing in a tournament last weekend, there were a few rainbow puke games that made ball tracking very difficult. On F-14, when the ball was in the upper PF area you could barely see it.
Think about playing during multiball and how much tracking that your eyes are doing, quick checks here and there, slight glances, trying to make nudge saves on the outlanes while hitting a jackpot shot at the same time. All of this is made incredibly more difficult when visibility drops.
Just say no to colour GI. If you absolutely must use colour, a painted incandescent bulb has less negative effects on artwork and visibility.