My experience with 100% merino wool including icebreaker is that it is far less durable then polypro. The perforamnce is great and I expreciate the odor resistance but it tears easier in normal use. I use seam sealer to seal the tears and it works but I have mountain hardware polypros that are darn near impossible to tear in normal camping use. Woold does standup better it you are messing with campfires as one good ember will melt a hole in polpypro.