The materials are sturdy and just by touching you can feel the quality.
I managed to put massive Tamrons 15-30 and 70-200 G2 and Sigma 150-600 and there was still space for Nikkor 85 in the main compartment. The upper part seems just perfect for Nikon Z6ii with 24-70 f4 on. Side pockets still able to contain a few filters and the upper compartment seems to have some extra space.
Zippers are very smooth and the rain cover is a great extra thing.
What made me quite surprised that when I fully loaded the bag and tried to put it on, the upper-right buckle just unlocked itself and the bag fell down (and one of chest strap hole was torn)! That was a great stress-test to check the durability of the frame (none of lenses broke!) but the buckle thing still makes me feel uneasy. I have no idea why the buckle button releases the lock. The way I put the bag on is not strange or unusual, to be honest. Actually, it unlocked few more times but I was ready - I put the bag on while seated on a couch so the bag just fell on a soft surface.
As I kept on testing the fully loaded bag, the buckle seemed to keep in place. Jumping, walking, fast walking, sudden pulling the handle - in all of the situations it remained locked.
My best guess is the load weight. Although I found no max load specs, I suspect that the gear is just too heavy (8,5 kg to be precise) which is a bummer because all the lenses which are packed, they are needed for my photo trips. Either way, tripod will be carried in a separate bag. I just hope that umbrella and/or water bottle can still fit.
***UPDATE***
After 6 months of active usage I can confirm that no issues occurred. I used it as a camera backpack and as a casual backpack (it's really great for the flights) and it's a solid 10/10. The versatility, design and build quality did not disappoint. To be frank, I removed the attached straps as I found no situations where those could be used (still). But I have them with me! And waiting for the chance to use them :)