I remember reading an article on them, and they do cool a bit better then AS5, but it wasnt a huge difference, considering that they can only be used on certain metals. I believe you cant use it on aluminum, since it will corrode it.
The differences between stock and AS5 is only 1-4C, and the difference between AS5 and the "liquid metal" was only around 1-2C, if I remember from the article.