Best I've Owned....Needs Some Work...
Summary: Ample capacity (despite prior reviews to the contrary) , very comfortable fully loaded, soft bottles/flasks are great (despite prior reviews to the contrary), the trek pole bungees/holders are unacceptable.
I bought two (one for my wife). We run-hike. We've used them three times. 12 miles, 18 miles and 44 miles. The later was a rim-to-rim-to-rim (R2R2R) in the Grand Canyon.
Trek Pole Loops: The up-front location of the trek pole bungees are great, but they fail to actually hold your trek poles unless your trek poles are so long-large that they're poking your ears and eyes out. We bought Leki Micro Trail Vario (trail running poles) specifically for the packs because the pole's trigger shark handle can lock onto the bottom loop on the vest (without which the poles would fall out more often.) I was able to complete a single day R2R2R by using rubber bands to better hold everything in place. Additionally, the stitching gave-way on my wife's pack at the cloth loop that holds the trek pole loop -- the loop fell off completely.
Capacity: We carried ample gear/supplies for an R2R2R with a food bag staged at the turn around point on the North Rim. Carrying enough food for the whole 44 miles would have required other storage (pockets on shorts or shirt, which I didn't have). We carried 3.0 liter bladders, with the two 0.5 liter soft bottles that came with the pack. The right hand "phone" pocket is too small for a Samsung Galaxy S8 although the S5 I had when I bought the pack did fit...barely. Overall, we have too many packs already. We bought these for the long treks through the Grand Canyon, running-hiking light but heavy-enough given the needs for that terrain.
Soft Bottles: Contrary to other reviews here, I liked the soft bottles a lot AFTER I replaced them with the straw type bottle available (BODY BOTTLE 500S SKU: 80461017). The tops that come on the bottles supplied with the pack are a problem in that the bottles are not easily removed and are much more difficult to put back in the pockets. If you use the straw bottles, don't fill them to a bloat because it makes the straw stand straight up and either poke you in the ears or in the eyes. Slightly less full and you can adjust them away from your face. I ran a multl-hour mix of Hammer Perpetuum in one and Isagenix Hydrate in the other with plain water in the 3.0 liter bladder. Two "packets" or 5 scoops of Perpetuum is as thick of a mix as the straw effectively handles. If you mix a fuel mix too thick, eat/drink some (suck really hard) and then get a couple of mouthfuls of water from your bladder and blow it through the straw in the fuel mix.
Overall: I am not versed well enough in materials to comment fairly on the materials, but from the beginning, I had some concerns about sturdiness. The failure of the edge stitching on one pack has increased that concern. The materials are light, but "seem" to lack the durable-sturdy character. Sturdiness aside and near uselessness of the pole straps aside, the pack performed remarkably comfortable through the riggers of an R2R2R.