2x draw weight, maybe on a flight bow.
On a hunting bow, 100% reliability trumps maximum FPS any day in my book.
Anyway, to chime in, I've used b-50, but I prefer the fast flight type materials. I use BCY8125, but for no other reason than I got a good deal. I'm sure all the fast flight materials are excellent. The main problem with b-50 is the stretch makes tillering a lot more difficult IMO. with fast flight it's no problem to low brace a bow and have the brace height precisely maintained. B-50 just stretches and stretches.