I just got a '50s style recurve (Chaparral Alpine) that is rated for FF string material. The string that came on it was very quiet, of some FF material, but it had wool wraps at the string grooves and fur silencers on the string. I made a new string for it from 8125, and it sounded like a .22 rifle. Scared me to death, as I thought the bow had delaminated (and I ain't afraid of nothin'!)
Anyway, I replaced that string with a B-50 dacron one, and it's back to being quiet again, with nothing on the string.
Ff has it's place, I'm sure, but with all the gyrations you have to do to make it quiet, I'm not sure it's worth the effort.
I'm certainly no expert, but that's my take on it.