I've alternated using the Savant 58 and Z55 all summer. Both work great, but luckily the fixed suspension fits me. Both were comfortable with 20 to 25 pounds in them. I'd highly recommend either - but take your gear to the store (all 30 - 40 pounds of it), and load it into the packs to get a feel for them. I might opt for the Z Pack, simply because they had a slightly beefier suspension.