Used the Trek for one short trip and a 14-day trek around Mt. Rainier, 15-25 lb loads. It worked quite well for me as long as I took care to pack it properly. I folded my deflated foam pad in thirds and put it against my back. This and the compression straps allowed the Trek to maintain its shape even if the pack was not full.
It weighs a bit over 2 lbs and holds 4650 cubic inches. I appreciated the extra volume up top to hold items that could not be smushed (cookies, crackers, rehydrating food, etc).