I washed then applied Mop & Glow to ours last summer, 2016. I can see the roof from a 2nd story bedroom. Still has a shine to it, could use a washing though.
I also cleaned the entire coach in the spring and waxed all but one smaller section. On that section I applied Mop & Glow. It's the only section that doesn't look like it needs to be done again. Like ZEP floor polish, just wipe it on, several coats, to get an even shine. No buffing and it does clean in case you missed any spots when you washed it. Oh, and it's really cheap.
Hank & Lynda
2003 Winnebago Adventurer 35U, Workhorse W22