Chris,
I've gone through 2 windshields: the Triumph Roadster screen (the big one) and the Slipstreamer Tombstone (small, narrow, like a flatter version of the Windvest). I sold the first one and abandoned the second because of the extreme buffeting about my full-face helmet. Since I ride with a full face helmet 95% of the time, I'd rather do without a screen.
I had a line on a used Windvest, but that seems to have evaporated. I'm not going to buy one new just to try it out.