Storage
The Osprey Stratos 50 follows Osprey’s tradition for two-zippered pockets on the lid, which make for super easy access to contents and plenty of room. The Stratos 50 also has a small hidden compartment in the very bottom of the pack that contains an integrated rain fly.  

The main storage area of the Stratos has three entry points including the traditional top entry storm flap, bottom sleeping bag compartment access and a large U-shaped zipper that allows access from the middle part of the pack. This middle U- zipper allows users to open the pack much like a suitcase and access the main compartment and contents of the pack. There is also a large zippered exterior pocket that allows for extra storage that can be accessed on the go, which provided several more organizational options.    

On the down side, the two side stretch water bottle pockets hold a 1-liter water bottle, but need to be a bit deeper to secure the bottles better. I also wished the divider between the sleeping bag compartment and the main compartment was removable. The Stratos 50 uses the conventional internal hydration sleeve to store up to a 3-liter hydration bladder.  

Comfort
Hip Belt 
The Stratos hip belt is lightweight and does not have as much padding as other packs in this category but was enough for good comfort. The wraparound effect of the hip belt also added to the hip belt comfort. The hip belt has two large zippered pockets that could carry a small camera, GPS, snacks, hat or gloves.  

Back Panel/Shoulder Straps
The Stratos has a suspended back panel that added to the pack’s overall comfort and provided the best ventilation of any pack in this category. The shoulder straps were comfortable and while the padding is not overly thick, it did provide good comfort.   

Stability
The Stratos was stable and comfortable carrying loads in the 30 to 35 pound range. The Stratos did not move around or float despite scrambling up steep ascents and descending rugged mountainous terrain. However, the pack did begin to float in the 40-pound range, reducing stability and comfort.  

Overall Comfort
The Stratos is comfortable overall provided you do not overtax the pack with heavy loads. The pack’s very lightweight feel, good padding and easy adjustments contribute to it competing well in this class of packs in terms of comfort.

Durability
The Stratos 50 proved durable in a variety of conditions. The zippers, pockets and fabrics all performed well despite weeks of rugged use. The Stratos showed normal wear that would be expected in rigorous testing and use.