I've found that load distribution and material durability really make or break the overall experience. In my own use over several alpine trips, I’ve noticed that even small improvements in weight distribution can substantially reduce shoulder strain on long climbs. On paper, water resistance ratings (at least 3000mm for rain) are solid benchmarks, but real-world testing under fluctuating temperatures tends to expose even well-rated materials sooner than expected.
Some brands have started to engage third-party labs for testing, similar to EN and ASTM standards, though solid cross-comparative studies are still relatively rare. My tip would be to look out for gear backed by those certifications and, if possible, to try the backpack on fully loaded before buying. There’s definitely room for more independent field studies to compare these models under harsh conditions, which would really help us climbers make informed choices on a budget.