Okay, finally had a chance to use it.
Washed truck, followed instructions, let it sit in the driveway for 15 minutes. Partly sunny day, minor breeze, 75 degrees.
Came out to find a totally dry and spot-free truck, with the exception of a few spots on the windows (I wash the windows anyway so this doesn't matter to me.)
So it looks like this product works as advertised, an amazing thing these days.
John