I haven't noticed anything in that regard. Haven't done any scientific comparison, though. "not conform as as much to body shape", or as I think someone else put it, I sink into it less, it's more like resting on top.
Actually, I mis-spoke earlier: I have a 1.2 oz PolyD hammock, not a 1.4 oz one. I'm 190 lbs. You could always go with one of the nylon ones if you're concerned about strength.
Bookmarks