I, for one, don't think it is hype. I tend to use the recommended anti-freeze, mixed with distilled water, and I add a bottle of Water-Wetter. None of these are expensive, especially so compared to the cost of a new radiator or aluminum head. Although M-B is the only one to recommend replacing coolant every two years, I do it on all my cars. When I first tried Water-Wetter, it was in the Austin-Healey. They are notorious for running hot. One bottle in a roughly two-gallon system dropped the running temp about 10 degrees (f).

Having said that, though. It's your car and you can run any damn thing you want in it.

just my $.02,
Wes