I've never liked "Barn Door" fairings, and have wondered about the aerodynamics and the affect it would have on the bike's handling, but when I "inherited" my Triumph Rocket III from my older brother it had a lot of Triumph accessories, including this see-thru fairing thingie.
It's not tall enough to keep the wind out of my face (although I can move it up a bit if I like) but it keeps most of the rain off me in winter, and the bugs outta my teeth every other season. I keep meaning to take it off, but there are a lot of bugs here this time of year, and they taste like #$%*. Cheers, Terry.