We cut some poor corn in 14' (drown out) with their corn pans and they work awesome!
They also work pretty decent in sunflowers.
We used them on a FD70 and I think they would have worked better on an auger head but was still very impressed.
Surprisingly the capacity isn't at the huge loss you would think with all of the extra material. When I was in 100 bu corn with an 8 row corn head on a 1480 and my brother was cutting with a 40' FD and a S77 in 65-75 bu corn he was out cutting me acres wise. I couldn't believe it because I was moving a steady 7.5 mph.
They are a good product and simple on/off is really nice. Also the customer service from flexxifinger is incredible, they will show up on your farm to assemble the whole thing.