This daypack features an innovative back panel that puts ventilation and load-carrying first. Updated in Spring of 2017, the back panel allows the user to adjust the torso length and the hipbelt no longer has any seams, both aiming to increase the comfort of this pack. Unfortunately, the suspended mesh back panel also happens to cut into precious space, affecting how many items it can carry. This could be either a deal breaker or no big deal, depending on your needs. In addition to the back panel, the Stratos has convenient features for hikers such as an ice axe carry and an easy to use trekking pole stash system. If the volume of this pack isn't enough for you, Osprey implements the same design in a bigger size with the Stratos 34 for $30 more.
The Gregory Salvo has a similarly designed back panels, but leaves less of a gap between the main compartment of the pack and your back, which means that it is a little less ventilated; however, it does hold weight slightly better. If you are looking for a pack that can hold a lot relative to its weight and bulk, try the frameless Granite Gear Virga 26 or Deuter Speed Lite 20.