I did have the chance to test it a few weeks ago, but something tells me that those who have made rave reviews of it, aren’t the ones who are used to backpacks or they where just lucky that it fitted.
Harness and adjustability is essential when carrying heavy loads. I know this from numerous backpack trips. If it doesn’t fit you’ll just end up with backpain and an awful trip. This is where this backpack, to be honest most camera backpack falls apart, these are simply not very comfortable, due to lack of frame (means it dos not transfer the load unto your hip properly), lack of adjustable torso length and properly designed harness. Yes it’s nice that the shoulder straps doesn’t touch the ground when opening the back, but it also means that you can’t adjust it and that it’s not perfect to carry around. Where I do agree with the reviewers is that the layout and solutions inside the pack is best in class . However if it dos not fit, it doesn’t really matter. I ended up with the Tenba Axis instead, not because it’s perfect (it obviously has its design flaws compared to the Lowepro) but because I actually where able to get it to fit.
My advise is try before buy, no reviews or recommendations is going to tell you if it will fit, this is vastly more important than the internal design and layout.
However I think the better once are F-stop and Atlas as these to a much higher degree follow the basic of a traditional backpack. So if I had to travel for extended periods, those packs is what I would be looking at.