I have an older Camp Trails external frame pack. It's in perfect condition (mostly due to being used once about 20 years ago and then put in storage until last week). I compared it to the weight of newer internal frame packs, and it's just as light, and just as comfortable for me. The only advantage to a newer pack is that I can put a hydration bladder in the new ones.
How can I get a hydration bladder in an old pack that doesn't have any place for one? I really like being able to just sip out of the tube on the trails as opposed to pulling out a water bottle all the time.