I have a dueter act lite. It carries very comfortably and well balanced. Ie: great harness, frame, and shape (narrow, curved in over shoulders).
The shoulder straps don't feel narrow (my golite straps do though). The padding is very supportive.
The adjustable torso is great - custom fit with winter or summer clothes. More stable / less wobbly than using load lifters to adjust the torso length a little.
The big things I don't like are: it weighs 4 pounds, and it has an air vent channel where the lumbar pad should be. Without the lumbar pad, the hip belt slips downward in the back and I have to readjust its position every 15 minutes to keep the weight off my shoulders when carrying 30 pounds or more. This is a fit issue, and YMMV.
REI also sells the lighter dueter act zero which is the same pack, but with a removable lid, no bottom access zipper (useless IMO), and a large bellowed fabric shovel pocket rather than the small stretch mesh rear pocket. The stretch mesh pocket is durable enough and holds a heavy duty gortex parka fine though.