L.L.Bean Stowaway Pack vs AER Go Pack

Here's why: Stowing it into its own pouch is a chore; and, results in a lump. I recommend a larger included pouch. It's easier just to throw it flat in my luggage, if I'm looking to take an extra container. The straps might better fit a child, or someone with a seriously narrow frame

These are going to be more suitable for ‘true’ one bagging (ie when you travel without a checked bag). If you decide to opt against a checked bag, perhaps look at a packable day bag and one of your options above, or take a look at the Peak Design Travel Bag, as this is designed with photographers in mind, is effectively a big bucket of a bag, and can expand from 35-45l (although I think when expanded to the full 45l it is slightly too big for most airlines). For a daily carry, you ideally want to be looking at something 25l or less, even under 20l.