Water Wetter, Evans NPG+ watterless coolant, who's right?

[Martin]

I read somewhere that Water-Wetter breaks down surface tension and makes liquid flow more effectively over surfaces and fills in crevices of a cooling system. Ive heard of someone pouring Water Wetter into a lake and watched the ducks sink.

I wonder why Prestone doesn't have the same capabilities as Water Wetter. Anyone know the downsides? Does it corrode the cooling system?