I have been experimenting with both for about the last 6 mos. I shoot 4 different bows about equal amounts of time, and with puffs made with wool yarn on two and the other two being acrylic, I cannot tell any difference. I haven't had to replace any of them. I haven't gotten them wet so don't know about that. I suspicion the wool yarn might hold more water but dunno. What I do know about any puffs I've ever tried is that if they do get wet, expect a shower when the first shot takes place.
They both look sharp!!