I got this bag in Ursa prior to a two week trip to Europe, and planned to use it as my carry-on under the seat with a Hartmann duffel as my overhead/checked bag. I have LOVED the backpack so far. The straps are super comfy, even when fully loaded with a laptop and other heavy stuff like books and the little bottles of booze I purchased in the main compartment. It has fit under every airplane seat I've tried so far, including the smaller crafts with only 2 seats on each side. I was worried at first about how easily things at the bottom might fall put when I unzipped the front compartment, but they really don't: firstly the zipper is super sturdy and doesn't open further unless you pull the tabs, and second the shape is designed so even slightly wide things are cupped in to the body of the bag even while it's standing up with the flap open. Genius. I love the bottom compartment too, it's perfect for an extra pair of shoes.
I'm a female who is 5'3" so a larger pack might have looked silly on me, but this one looks just right (although I have to adjust the back straps to almost their tightest). Check out my suave reflection in a window in Nuremberg ;-) And the Ursa color is a beautiful brown.
Overall very happy. I'm carrying this along with a Le Grand Derriere on this trip, which I will review separately: they are a great travel pair! I pack then differently for the plane than for a day trip, but love that I can bring one bag and use it many ways.