Stability
One of this pack’s strongest suits is its stability under very heavy loads. I used the Deuter Aircontact 75+10 on numerous backpacking trips carrying loads in excess of 50 pounds and found it to be very stable. The pack did not shift, weigh me down or feel uncomfortable on steep ascents or descents. Although my load did not exceed 55 pounds on any trek, I’m confident this pack can handle heavier loads with similar results.

Overall Comfort
Deuter’s Vari-Quick system makes it easy to adjust the torso length of the Aircontact, which adds to the overall comfort of this pack—and makes it more versatile when transferring between users.  The hip-belt and shoulder straps are covered in a very thick, ventilating hollow chamber foam that is both comfortable and breathable.  Combine this with the stability of the Aircontact and you have a big pack that exhibits small pack comfort. 

Pack Access and Organization
The Aircontact 75+10 has top and bottom zippers, and an additional suitcase-style full-length zipper that provides full-panel access. These various entry points made it easy to gain access to articles and gear. The lid on the Aircontact has 1 large outer and 1 underside pocket that provides a variety of storage options.

Pockets
The pack has a side-stretch mesh stash pocket on each side, which are large enough to hold a 1-liter water bottle and deep enough to prevent bottles from escaping. The Aircontact also comes with an incorporated rain cover that is stored in a built-in pocket.    
The Aircontact 75+10 provides an interior hydration sleeve pocket, but the pocket is not deep enough to hold a 3 liter bladder. Unfortunately, the top attachment (where you’d hang the bladder) is not secure and comes loose easily, causing it to slide down inside the pack.  

Hip Belt
The Aircontact 75+10 comes with anatomically shaped hip fins that provide a good wrap on your hips. The padding is very thick layer of soft foam—and provided a very comfortable and secure fit. The straps on the hip-belt are easy to adjust and a large zippered hip-belt pocket on one side allowed me to store small items. While this hip-belt performs very well, I do still wish it had a size adjustment which would make it easier for larger and smaller torsos and waist sizes (for example, a large torso length but a medium waist).

Backpanel
The Aircontact 75+10 has an extra air channel that provides some ventilation between the back cushions, which adds to its breathability.  The backpanel is cushioned with Deuter’s ventilating hollow chamber foam, which is quite comfortable and allowed air to flow between my back and the pack.  Overall, the airflow through the backpanel was adequate, but not spectacular.  

Durability
The Aircontact 75+10 proved to be tough and durable over months of use in a variety of conditions. It’s made with a Polyamide-fabric, which is extremely abrasion and tear resistant. This material also repelled dirt and debris very well.