Comfort/Fit
The Osprey Aether 85 performed best when it was loaded down heavily. The shoulder straps are well padded and the waist straps, which can be custom molded, are able to maintain the firm-but-comfortable fit necessary for walking with very heavy loads. The ventilation system also does a good job of getting air to the back, even while loaded down. This system extends the mesh up onto the waist strap, which enables it to pull air from a greater surface area and cool you down more effectively, almost like a car scooping cold air from the front to cool the engine down. 

Storage
The Aether does a good job of maximizing its storage capabilities. There is a ton of external storage, with the gear straps just above the seat, three lateral buckled straps across the back, four vertical buckled straps, and two compression straps on either side. More importantly than exterior storage, what all this strapage provides is very good compression, so it’s comfortable with a range of loads. The body compartment has top and bottom entry, and a third horseshoe entry into the center of the compartment.The brain is detachable and becomes a daypack, and there is also a second lid that will come down in its place. 

Stability
The waist strap of the Aether 85 provides almost no pivot, but the frame is flexible enough to allow the back to bend and twist a bit to stay balanced and move efficiently. The pack’s center of gravity when fully loaded tends a touch higher than the other bags in the set, but it wasn’t dramatic enough to impact the user’s balance, even if they’re off trail or in rough country. And to add one final but not insignificant point, the positioning of the tent straps on the bottom of the back rather than the bottom of the seat, means your pack will stand up straight during trailside breaks. 

Durability
The Aether 85 is sturdy from the ground up, beginning with the reinforced seat and ending with an effective water resistant treatment on the back and top. The tent straps are thin but all the other webbing seems to be well sewn. The load lifters are particularly heavy-duty, which frees up the top of the shoulder strap to focus on padding, which leads to a much more comfortable fit. 

Extras
There is one gear loop on the back that can be used with either of two loops, another gear loop on the back that can be used with a medium or large loop on the bottom, and a trekking pole tether on the left shoulder strap. There is a zippered hip pouch on either side of the waist strap, both water resistant.