TLDR version: I have used a lot of high end backpacks over the years ($200 - $400 price range) and this one is the best I have ever owned. I've had it for about 2 months, during which I've used it for work, photography, and international travel. Build quality and functionality are excellent. Overall design is very refined. Details are thoughtful. Highly recommend!
Details: I deliberately bought the smallest PRVKE model simply because if I have a larger backpack then I will put more stuff in it and have more weight on my back. It turns out the Lite version is a great size for what I need to carry: a laptop, DSLR camera with 200mm zoom lens, chargers/cables, snacks, rain poncho, and various pouches of small items. The reconfigurable dividers in the main compartment provide great padding and stay firmly in place. I need an expandable section for a fleece and food when I travel, and the roll top worked perfectly in this regard. On occasion I carried a tripod or other larger items using straps between the 4 loops on the back. The side pocket for the camera worked well for me, including one week in which I was shooting with a much larger lens (100-500mm zoom). I don't use the chest strap except for long days of walking. When I did use it the backpack stayed in place much more securely. Note: I had to get a new water bottle that was small enough to fit in the side pouch (my 32 oz bottle didn't fit). I suspect the larger PRVKE models have larger side pouches.