I value having a face, so no thanks to your flip up's, your open faces etc etc etc I have another full face with more 'slot', and a clear visor with a sun visor inside, but it's for when it is proper winter, not yet.
I think that the stupidest looking thing ever is some dude with all the gear on, and the front of his helmet flipped up, you know, like a police motorcyclist, trying desperately to give you a telling off while looking ludicrous.
Each to his own mate, you do you. I'll stick with proper full face helmets. I wonder why motogp or motoamerica riders dont wear flip ups?