I prefer D 97, its only a little louder than D 50, but doesn't buzz as long as D 50 after the shot because it doesn't stretch, you can make strings that are 10 -15 fps faster than D 50 if you make skinny strings, 10 or 12 strands instead of 24, they are still plenty strong 500 to 600lbs. FF is louder than D 97 and seems to stretch. Can't tell any difference in performance between endless loop and flemish, but I prefer the looks of flemish and shoot them on bother recurves and longbows without problems.