Okay I went to Cycle Gear a couple weeks ago to get a pinlock insert for my helmet but they had none compatible, so I got a Fog City.
It does as advertised, it did not fog up. BUT, night vision kind of sucked due to reflections and refractions, and it just didn't look clear anymore. They even had a warning to not use it at night. Duh, that's when I need it the most! I don't need it during the daytime! Even daytime vision was annoying although it is adequate.
I slapped my other clear visor on this morning. I wouldn't get another one but I'll save the Fog City visor for really, really cold days where fog is a real problem. Barring a better anti fog solution for which I am still searching.