I was looking for a new backpack to use for work, city, hiking and as an underseat bag. I bought the Siena Pro 13 in all black, and am very pleased with it. In comparison with my old backpack, it's a big higher so it can (just) contain a folder with A4 documents in the laptop compartiment, perfect for work! It's softer on the shoulders, lighter, and very stylish. I love the many compartiments in the front for quick access, and how sleek it all still looks. I haven't used it as an underseat bag yet, but as it's the same width as my old backpack, I'm sure it fits (btw. I always place the bag on its side, not on its back or front like in the pictograms shown. This way you have more than enough room for your feet next to the bag) The bag stands on its own, even when empty, which was an important feature for me. The bottle pocket is large enough, but the elastic is too strong, I've been trying to stretch it a bit, but if that doesn't work, I might cut it and make it a bit longer. For now it's a bit of a struggle to put the bottle back. The pocket also can be used for your umbrella. In the big compartiment it will hold: a toiletry bag, a foldable down jacket, a lunchbox, an umbrella, ... and there's room left. ps: I had to buy an adapter for the USB-A port, because my phone uses USB-C.
