I have no personal experience with it, but it doesn't seem like all that great of a product, especially for the price.
One thing that really throws me off is the specific heat of the Evans NPG+ coolant, which is about 60% that of plain water. This basically means that for a given amount that goes through your engine, it can only take 60% of the heat away from the engine compared to water. Seems like a decrease in performance from what I see.
Also, what's the point of having a coolant that boils at 191C (375F)? If you run hotter coolant temperatures, than the oil would become too thin, an engine not designed for higher temperatures would experience premature fuel detonation, and the higher temperatures would cause premature failures of all coolant hoses.
But the avoiding rust part is nice as well the larger margin for error should you have a sudden cooling problem. Personally, I would just use distilled water and a bottle of Redline Water Wetter.