Here are a couple dyno sheets. The filter top got 9 more hp in this example. It was a back-to-back test. I also got my highest dyno numbers using it. There is a science to this so I don't claim to know the answer, I suspect that after reading all of your posts you are all right; it depends on the car, jetting, air flow, turbulance and that dyno testing may not always be conclusive, but in THIS CASE, the filter top made more HP. It seems an unreasonable conclusion that the filter top would never produce more HP for any car set up or engine and carb combo or that it will always have turbulance or air flow issues. But, it seems just as unreasonable to dismiss all of these first hand accounts about airflow problems, but now you have at least one dyno test to support the "pro filter-top camp".
Dyno Sheet - HP and Torque Question