I had a full screen on my M3W. It offered good wind protection, but the plastic scratched easily and in the rain it was not easy to look through rain-spattered goggles/crash helmet visor and a screen that did not have wipers. We sprayed both with Rain X, which sheds some of the water, but visibility was still a problem.

That led me to go on my current (sort of) M4W for smaller, glass screens that could be folded down if necessary. However, one does get wind-blasted at speed and, given a choice, I would go for scratch-proof plastic with wipers - as in Trikings. I wonder why MMC has not offered a wiper option.