Toppers are only about $300-$350 when factory installed, which is how I get them. We use our fiver about 120 days per year. In hot weather it helps keep the rv cooler since the slide out roof has minimal insulation. Under snow and ice conditions it keeps the roof from becoming iced over, just close the slide out and everything just drops off the topper fabric. And under more typical conditions, the topper does keep debris off the roof.
Downside is that the larger toppers can flap in high winds and water will pool in the center. I can live with both. Dust does collect on the slide out roof and can't be cleaned with the slide out open. Some people do nothing, but once a year, I clean the dust off from the inside with the slide out closed using a step stool, shallow water pail and a sponge.
Texas Baptist Men-Retiree Builders member since '01
13 Silverado 3500HD D/A, 2wd CCSB srw, custom RKI bed
11 Cruiser CF32MK