It cannot be this subjective...can it?
There's gotta be a consensus of which shield blows the most amount of air over your helmet; the one that promotes the least amount of noise and turbulence on the side of your helmet.
How can that be an impossible thing to measure, or even feel?
If I had to take a gamble on a windshield, I would GUESS that the taka or the Klock Werks are the most effective. I had flared-tip shields on other bike and they worked best. There are alway those huge ones but you gotta look 'through' them.
I bet the Madstad and the Windbender work also, but the air that comes under the shield lowering the upper part air-flow pressure couldn't possibly be good on cold mornings. I rode a shield with that vent-hole in the middle (but no vents) in a cold day and that was not good. I imagine that air coming from under the shield is even worse.
That's it, I am buying a car...NOT!
A giant star blew up, elements combined, a long time passed and then, there you are. The mother of all mothers, even yours, is a supernova.