I shoot Fiocchi Officials on the 100 birders and Fiocchi TT ones for Practice. I was offered some F3's so pushed a slab though my gun. In my opinion, they feel fast (probably down to the punchy recoil)! Pattern well and smashed everything that was out there. Too punchy for me compared to what I am used to. I tried F-Blacks but for me they pattern with a tight centre pattern resulting in dusts or chippy breaks. I have found what I like now. The Officials in Italian 7.5s (English 7's), and the TT ones same size. Nice even patterns and soft on the shoulder.
For what it is worth, I was shooting at Doveridge at the weekend and the weather was a bit awf....... Doveridge produced some excellent testing stands, but the wind was pushing the clays way beyond what I was shooting at. Certainly 90+yds, but the 7 shot and 3/4 choke broke them nonetheless.