Using the Exos 38 M I have been hiking Scotland for more than 1000 kms (naturally paying special homage at Boat of Garten, guess why) with a (full outdoor) base-weight of approx. 10 kgs which at some days went up (food and water) to well above 15 kgs. This fine piece of equipment didn't let me down once. So little weight and so many features! And everything remained perfectly intact: the tiny zippers, the slim straps, the whole filigree yet sturdy construction ... and the curved frame really helped keeping my back dry. There is only one - minor - issue: the borders of the shoulderstraps can be a bit cutting in, espc. if the carried weight is above 12 kgs or so. Even though I found my ways with it, I wouldn't mind a little cushioning or an aligned design there. (My wife reports the same issue with her Exos 38 S also at lower weights.) The large mesh pocket is an enormously stretchable, very forgiving and most welcome feature - you might be tempted to forget that it's not quite adamantine, so don't be displeased if you create a few add'l holes there. Summarized, the Exos 38 is truly a state-of-the-art product. Go for it!