"One man's opinion." Your mileage may vary.
) the air-flow over the front & sides of my 2013 RT creates a 'still air rain free' zone behind the windscreen that extends out to the back of the trunk (helped by the 'whale tail' type rack on the top of the trunk... 
) and it also causes all the rain that hits the windscreen to bead and run up off the screen and out to the sides (it makes a very interesting/attractive pattern when you're riding into the sun setting on the horizon thru a downpour that's dumping out of the clouds immediately above you, but which are high enough that they're not blocking the setting sun on the horizon! It's almost as good as the pattern seen when riding into the sunrise and the moisture beads formed by the morning mist on the screen all blow out and away from the centre of the screen! 
), and it creates an almost completely 'rain free' zone behind the screen so that both my pillion and I don't have any issues with too much rain on our visors either; even tho my head mostly sticks up above the top of the windscreen - even when the screen is in the fully raised position and my head is above it, it's still in the 'deflected air' zone. We basically just don't get wet unless we slow below 30 mph-ish &/or stop! And what little rain does hit our visors does the same as the rain that hits the windscreen; it's blown up and out, then off into the slipstream behind us! 
