Re: the S2S pack, my wife and i have the day pack versions which are a bit lighter, smaller, but made out of the same material it seems. I was a bit disappointed with the lack of durability. I thought it being cordura and siliconized nylon it might hold up a bit better than it did.
Actually, my pack is still in good shape, but my wife's developed a hole towards the bottom. I'm not sure how that happened though, because it was on a trip i wasn't there for. She's not known for being careful or conscientious with gear i've noticed on trips with her, so it's possible it was unduly abused.
Would like to try a 70D Cordura, silconized version of same...or at least for my wife ; )
Also, the straps are quite slippery. I ended up sewing some linen-poly material on part of the straps to help create a little friction and to absorb some sweat.