i went to the my local REI, I wore both of the packs that I like fitted to me. Then, I asked for wear them in the store for 30 minutes each while I shopped. I also had 35-40 lbs of weight put in the pack to allow them to settle on my back and feel what that weight was like. After an hour of wearing both packs I better able to pick whick one felt better on my back. That was good for me. One of the packs I tried on was an ultra lite version. After 30 minutes it was not the most confortable one to wear. Just my two cents! You milage can and will vary!
