I would expand your search and take a serious look at both Gregory Mountain and Black Diamond series of Daypacks as I own models from both of these fine companies.
My favorite hands down is my Nitro 22 (Black Diamond) a zippered top loader because it has excellent organization, good hydration bladder option carry, and mostly important for the size and overall light weight it has a padded hipbelt, load lifters, etc. Internal plastic sheet and aluminum stay comes in two diff sizes and is very conforming to my back.
Backcountry.com easily has Thee best selection of Daypacks to purchase from a single store based in Utah. Moosejaw.com is another good company with wide selection. I recently bought (3) Mystery Ranch grocery packs sacks from them.