You need to be much more specific. I beleive there are multiple "waterless" coolants out there, depending on how the mfr uses the word "waterless."

I do know this particular brand of waterless product is highly endorsed by Ray Bochacz (he's a tech writer for Hemmings Muscle Machines and many others rags...not paid for his endorsements) over any other coolant, and he is a mechanic who certainly has earned my respect over the years, and for that very reason I have no reason to cry snake-oil:
http://www.evanscooling.com/

I haven't used it personally yet to comment. It is completely incompatable with any other coolant/water, so it takes a rather involved flushing procedure prior to install, to get 100% of old stuff out of heater core, hoses, engine, and radiator. This would obviously be a bit of a disadvantage.

Incidentally, Bochacz also wrote for High Performance Pontiac many times over the years. Here's another article where he references this coolant, among many other cooling issues that are Pontiac specific:
http://www.highperformancepontiac.com/te...de/viewall.html

In that same article, he specifically refutes the often-repeated statement that "water is the best coolant." He explains why people believe it, and why it is actually false from an engine cooling perspective.

He also shows a different Pontiac water pump plate mod than the one most often discussed here, basically an extra hole drilled in the plate to essentially ensure that all air is bled out of the pump. This might be worthy of trying on a car that continues to overheat, but the fact that Boomstick's car is producing a very hot radiator leads me to believe an airlocking water pump is not his problem.

If you can follow his discussion of coolant attributes in that article from beginning to end, you are closer to a chemist than I am...it frankly cracks me up when he starts that section of the article with a statement about "not getting too deep into chemistry..." but anywho it gives you an idea of the depth of knowldge Bochacz has on various topics, as it often takes me 3 attempts to read one his articles before really digesting and understanding about 70% of it...and largely taking his word for the rest.

So I say NOT snake oil, and indeed better than pure water or any other glycol mix, based mostly on Bochacz articles I've read...if you're asking about Evans anyway...