I'm not sure how to rate my water in terms of "hardness." I live in New York City and have been using the Mr. Clean product for over a month now. I've probably washed the truck about 5 times so far and can't complain. It does exactly what it says. Leaves your car shiny and spot free. I have not noticed the sediments that others have, nor the streaking...but then again, I have a Titanium colored T4R.
The only negative I can say is that it would take me less time to actually dry the car up with Chamois than to let it sit and dry. I've done both and gotten same good results.
Just so you know, I'm a car detailing freak when it comes to my cars. I did not buy this product for the sake of being lazy.
My full detailing routine includes a wash, polish, glazing, waxing, wheel cleaner, tire dressing, interior detailing and rain x. I figured the Mr. Clean system would help me save some time when I wash in between full-blown detailing sesssions. And it does. Sometimes, I simply drive off with the car all wet and it still dries spot free. The only thing that needs attention are the windows, which I like to address separately anyway.