The windshield absolutely does what it is advertised to do - sends the wind, dirt, bugs over your head! However if installed as required, it does a few other things that are not so good:
1 - the heat from the motor is trapped inside the cab, and coupled with no air movement from the windshield it is very uncomfortable to ride in in the summer. Would probably be great in the winter time!
2- the dust tends to settle on the inside of the windshield and on the passengers rather than passing thru the cab.
3 - the top of the windshield that has the angle in it to deflect the wind is pretty much at eye level and distorts the vision of both driver and passenger. I think it should be a few inches taller.
My fix for all of the above was to raise the windshield about 5-6 inches. This allowed for air to pass thru the cab, kept dust blowing thru and eliminated the distortion. I am worried about the support for the bottom of the windshield so I will be adding a piece of aluminum angle iron at the bottom of the windshield for support.
You should build a half windshield that is framed out with aluminum at bottom and not contoured to fit the body, since it doesn't really fit the body anyway.