Yeah, like several have said, it's not as good as water. The main things to look at for a coolant are the specific heat and viscosity.
The specific heat for that coolant is .92 cal/g C and water is 1.0, so it will only remove heat about 90% as well as water which is not good.
The other thing is viscosity, that engine ice has a viscosity of about .7cp and water is 1.0, so it is going to flow a little better than water that's good for reducing friction and increasing flow rate.
The other thing not noted is any chemicals that reduce surface tension, there is usually some small benefit to a soap or something that reduces surface tension. I know Ira-K mixes a couple of drops of detergent in his own mixture, it's probably worth some improvement.
But generally most automotive coolants are formulated specifically for the need to raise the boiling point and lower the freezing point, for pc cooling we better not have the boiling point problem..
The more I mess around with coolant the more I'm tempted to go with Ira-Ks mixture, pure distilled with some PT-nuke for biocide and a little glycerine and a couple drops of soap. Maybe I'll pick up some color primochill tubing next time around and forget about the UV dye.