Comfort/Fit
The Osprey Stratos has one of the best back ventilation systems in this set. The padding in the shoulder straps also has cutouts where air can pass to the torso. The texture of the mesh will make it preferable to always wear a shirt while wearing the Stratos. The sternum strap has a wide range of adjustability, and holds in place. 

Storage
The Stratos has a back sleeve which contains both a zippered and non-zippered compartment, allowing for a variety of gear to be stored in an easy to reach spot. There are two entry points into the body compartment, at both the top and bottom. The bottom of the pack has a small zippered pouch for the pack’s included rain cover. 

Stability
The stability of the Stratos is aided by the two diagonal cinches on either side. These are cinches, not buckles, which miss an opportunity for more exterior storage. The brain clips down on the body only halfway down the bag, which also limits compressibility, but helps the brain extend upwards easily. This pack is comfortable and stable with loads as heavy as 40 pounds.

Durability
The Stratos is a well thought out backpack, from design to manufacturing. The exterior has a moderate amount of water resistance, and will keep the user’s gear dry even in windy or light rain conditions. The top and bottom of the body, where the frame puts extra stress on the fabric, is reinforced without driving up the weight very much. 

Extras
The Osprey Stratos has a whistle on the sternum strap and two hip pouches. There are two gear loops on the back of the pack and a stow strap for trekking poles on the left shoulder strap. There are also two gear straps on the bottom, which increase its storage capabilities.