The ergonomic back padding is generous to say the least: three big orange slabs of foam provide ventilation, and the curved arm straps are comfortable, though lack smartphone pockets like the Squeeze had. There is a padded sleeve below the thick, padded top handle to the Flow where an iPhone, MP3 player, or other smartphone can be tucked in, but its placement while wearing the Flow could leave your treasured gadget vulnerable to being stolen.
The Flow can also be used as a camera bag: a zippered pocket oddly located on the front-bottom of the bag has expandable space that can fit a large dSLR. We're not sure we trust having a camera on the bottom of the bag, but the padding at the bottom is as thick as it is everywhere else. When it's not in use, the pocket collapses via adjustable Velcro straps inside to make more room in the interior. It's a neat idea.
This is not a city commuting bag. We tried wearing the Flow to work in New York City using the subways and found ourselves nearly bowling over fellow travelers. Wearing the Flow feels like wearing a small suitcase on your back. It does handle its weight well, but it has a feel that's less like a standard backpack and more like armor. The Flow's bulbous size makes it prone to tipping over when placed on the floor, but its excellent thick handle on top is great for carrying short distances.
We'd recommend the Flow, instead, as a fantastic airline carry-on backpack, or a general gearbag for weekend car trips. Roomy and sturdy side pockets, lined with slightly elastic neoprene, are useful for everything from water bottles to bundled power cords (just don't put them in the same pocket). We never lacked for pockets on the Flow. And, again, we appreciated that all of these compartments never interfered with the laptop sleeve tucked away--nearly hidden, in fact--against the back. It's definitely one of the most useful and well-designed large bags we've seen, but we don't have an urge to use it every day, like we did with the Squeeze. It will remain with your luggage, not your jacket and keys.
The Booq Boa Flow comes with a limited five-year warranty covering defects from "normal use," and won't apply for damage that Booq deems was caused by physical abuse or negligence. The bag will be replaced, or if the Flow isn't available, be substituted with a percentage value of store credit based on lifetime ownership of the bag.