We are pro-toppers for previous mentioned and these reasons:
1) We stayed at Sheridan WY one night and it rained a little bit. When we brought the slide in the next morning, about 1/4" of ice had formed on the topper and it rolled right off. The top of the slide was dry.
2) Yes, rain will puddle up on the toppers but when the rain stops, we simply bring the slides in and let the water run off the toppers then put them back out and they dry in no time.
3) The toppers keep pieces of bark, leaves, pine needles and pollen off the top of the slides. Recently, I was at the container store and bought a "casabella microfiber extendable filament duster" for under $20.00. The fluffy duster is washable and it can be shaped to a 90 degree angle or to your preference and the handle extends far enough to reach the topper on top of the bed slide. We haven't tried it yet, but think this will work much better than the broom. It should work nicely between the top of the slide and the topper if necessary.
4) No getting out the ladder to sweep off the top of the slides.
5) The toppers seem to help keep the camper cooler.
6) We were in Amarillo one night and a whopper of a storm blew in on us. The toppers were flopping pretty loudly so we hit the button and brought the slides in, turned out the lights and went back to bed. When we woke up the next morning we put the slides back out.
For us, toppers are a must. We won't be without them.