I still prefer B50/55; it's quieter than the other stuff I have tried (FF, FF+, D75, DF97, UC). The stretch/creep doesn't bother me (learned to minimize and live w it long ago). To me it's not "shock", it's spirit; the new stuff feels "dead", and not in a good way. YMMV.
My friend broke the tips on two Groves bows from the 70s using FF when it first came out, so some old bows do not handle it as well as others. His other Groves w Dacron only are still going strong.
Not definitive, but I'm not experimenting w my old bows.