Comfort

The Osprey Aether Pro 70 earned the top mark in Comfort; at 3.9 pounds, it is by far the lightest pack of the four we looked at with this test. Osprey’s Airscape back padding allows a bit of airflow across the back, though that ventilation is limited. That padding sits comfortably on the back, though, during use. The padding on the waist belt includes some ability to be custom molded in-store to improve fit and comfort – but note that customers are prominently warned to not perform the customization at home in their baking ovens. The shoulder straps are just over two inches wide at the clavicle and have enough padding to prove comfortable on our test trips with loads of 30 pounds.

Storage

The Osprey Aether Pro 70 proved to be the best performing pack in this group of packs. It featured a threaded Z-cinch compression system, which quickly and easily locked down whatever we stuffed in and prevented things from shifting around. It is also the only pack in the test group that could reasonably accommodate carrying a pair of skis. Strapping on trekking poles, mountain axes and other hardware also proved easy and effective. There is only one compartment in the top pocket, and there’s no divider in the main bag. The top pocket easily detaches. There is no back sleeve, and only two external pockets to weigh you down or accumulate stuff that you don’t need in the backcountry.

Stability

Osprey Aether Pro 70 features a unique pack frame. All of the other packs in this test group employed either vertical aluminum stays or a box-design of rounded aluminum stays. The Osprey combined the two, with a U-shaped design that blends the light-weight flexibility of the former style, while still preserving most of the stability and performance of the latter. Using the straps on the bottom of the pack bag to secure a tent can help with balance when the bag is full. The pack bag dimensions are relatively square, not tending towards top-heavy nor bottom-heavy. One possible exception is when the pack is set at a low torso length, where top-heavy packing is more likely.

Durability

The sides of the waist belt and the sides of the main body of the Osprey Aether Pro 70 are well-protected and should stand up to most passing-between-tight-trees or canyon country friction. The exterior material’s treatment leaves it pretty water resistant; though we still put our sleeping bag in a dry sack but gone are the days of lining the main compartment of a pack with a trash bag. The top pocket is beefy and can stand up to the weather. The zippers are about average, and the buckles are made of plastic and are also about average for this set. The pack’s durability is excellent given the lightweight design.

Extras

The pack’s one dedicated water bottle sleeve hangs low from the side of the pack, to about the waist belt. Another zippered pocket can be opened to accommodate another bottle or assorted knick-knacks. Straps on the bottom of the back, just above the seat, can serve as a small kickstand to keep the bag upright when there’s nothing to lean it against. A trekking pole tie on one of the shoulder straps, and two rows of sock driers (or solar panel tethers) on the top of the top pocket.