Well if it doesnt have an advers effect on temps, who cares about the staining of an area you can see with a cooler on in the first place. I never heard that Liquid Pro's left over silver smuges caused any negative impact on a new TIM. As for how effective it is, all the reviews I've seen show it between 1-2 degrees worse than Pro. Buts thats still puts it right up near the top. I'm curious as to how well it will work for things like chipsets and GPU's.