I am sold on the waterless systems. I started years ago with Dri Wash then switched to No Wet. Both of them work well.
Last year I got the Wash Wax All system and am very pleased with it. Yes, nothing beats a real water/soap wash when the coach is really dirty but I am satisfied that the Wash Wax All works very well in most cases. Do you get scratches in the paint??? All I can say is my coach is 7 years old and most folks who see it say they think it is new. If I shined a light on it at a certain angle could I find some fine scratches.... probably. I suggest no one can keep, use and clean one of these beasts and never find some fine scratches.
When the coach is beyond dusty and I decide to use the Wash Wax All, I follow their instructions to wet the mop first (wring it out well) with water. I then spray the solution on the wet mop head and also spritz some on the coach. That has worked for me.
I wash the roof at least 3 times per year myself with Turtle Wax Zip Wash. It does a good job. If I am in Myrtle Beach (like now), I have a mobile wash guy wash the entire coach including the roof. Once per season I have the same guy wash and polish the coach. He does a great job. Watching his young guys do that while I drink a cold beer beats doing it myself
.