I have a National Cycle's (NC) Deflector (about 14" tall) and think that it is a good mix or protection without feeling like a true windshield, for riders 5'10" and under (see signature picture). However, I would recommend something bigger if you ride a lot highway miles (I don't). On the highway I feel can a good bit of buffeting along the top of the helmet, but there is little wind pressure on my body. Quite tolerable for short highway runs. On back roads it is short and small enough to almost feel invisible, while still provides some bug, debris and wind protection. NC windshields also remove in seconds. The deflector option is not best in class for any one area (highway, bugs, wind protection, etc.), but it provides just a enough protection and style (IMHO) for mixed riding.
Chris Glennon - Portland, OR