I have the Triumph summer screen. It keeps me from having to grab the bars tight to hold against the wind at highway speeds so I keep it on now.
Last week coming back from LA we rode 3 hours through a good solid rain front with 20+ mph gusts from the SSW (we were headed west). I could feel the wind pushing but it was no big deal; even with the wet conditions it held firm to the tarmac. (I remember riding smaller bikes where I was pushed sideways in the lane, dry road, and had to correct at each gust.)
As for the buffeting caused by a screen, mine is small and it doesn't seem to matter much. On my brother's HD with a really big windscreen I could feel the front wheel wiggling when in the vortex behind a trucker, kinda unnerving. I would rather look over the top of my small screen and have the wind in my face than ride his with no wind where I have to look through the plastic, like being in a cage.
