I like the concept and many details of this pack, and the price is very reasonable, but have a few questions and concerns.
Try as i might to reduce my load, i'm still usually up into a 55–65-liter pack for multiple-day, non-winter outings. It goes up from there in the cold months. But maybe adding a front pouch like the Z-Packs front-mounting Utility Pack, i might be able to get the 40-liter size to work. The hip pockets on this pack look larger than most, so that might help. Even with all that, it might be a little small.
Another sizing thing — my torso is about 20.5 inches, just over the top of the listed range for the M/L size, so it might be a little short on me.
Elsewhere, i see it mentioned that the total "wrap" of the waistbelt is 26.5 inches. Is this the distance from the end of the padded area, around the back, to the end of the padded area on the other side? I've tried some packs where the padding stopped just short of covering the body ends of my pelvis so that only the webbing strap contacted there. I've got a 37-inch (or so, depending on the time of year) waist, and i need about 30–31 inches or so of "wrap" on the padding (if i'm interpreting that term correctly). My comfy (but heavy) Osprey Xenith 88 i use in winter has padding that extends about 32 inches.
Another concern is that i don't see any strapping on the exterior of the pack that would allow for lashing on something like a rolled tent or sleeping bag across either the bottom or top. Sometimes after a resupply for a longer (5-day or so) stretch, something normally carried in side the pack gets moved outside to temporarily make room for extra food and/or water.
I've yet to find a good use for shoulder-strap pockets. I like to carry a pint or so of electrolyte drink in a bottle bungied to a shoulder strap, so having the pockets built in is a downside as they get in the way of that.
Also, i usually carry my "working" water bottle (the one i drink from as i'm hiking) in a pouch that i attach to the waistbelt so it rides on my hip. It's usually a simple connection between the pouch and the belt, but from the photos, it's not clear whether the belt pockets might interfere with this.