Like Berghaus’s Expedition this pack is designed for mountaineering and climbing rather than backpacking. It would be more suitable for a winter Munro ascent than a hike along the Pennine Way. However unlike the Expedition the harness system and capacity are fairly well matched. Up to 12kg it’s comfortable. Above that I think I’d soon get sore hips as the hipbelt is quite thin. The stiff frame does transfer the weight well. Unsurprisingly the pack clings to the back and stability is excellent.
The opening is very unusual, being a combination of a roll top and a lid. A sleeve that runs round the front and sides of the pack at the top covers the load. Over this goes a large asymmetrical collar that is much higher at the back than the front. Two drawcords and one hook clip close the pack securely and can be opened quickly. Virtually all gear has to go inside as there are no front or side pockets, not even shallow wand ones, and only one small flat one in the top. There are side straps for attaching gear and daisy chain loops for more straps or cord if needed. The pack is tapered from top to bottom. Patagonia says this is for elbow clearance. It also makes access to the contents easier than in packs that are wider at the base.
If you want a pack for climbing as well as backpacking and your loads aren’t too bulky this pack is worth considering. It’s not ideal for most backpackers though.