I was going to share a lot more about how to buy the Setout, but Tortuga has discontinued both it and its accessories. I will try to find a second set of packing cubes eventually, but I am very glad that I bought the rain shield ahead of time. Without Tortuga selling new rainshields, I can't recommend the Setout to anyone since it's not waterproof.
Instead, I'll make my suggestions for what I liked about the Setout, and then you can look for a backpack that meets your needs from what else is on the market:
- Get a 35L backpack. International flights and US crop dusters usually can't fit 45L bags, so you have to gate check them (or worse, for international, check period). The Setout will fit into a small overhead bin without trouble, and will go under a seat if pushed.
- Go for a rectangular, single pocket bag (like you would for a wheeled carry-on), rather than something rounded or multi-pocket. The rounded corners of a traditional backpack prevent you from filling that space, and a divider just makes things less flexible.
- Lots of places rain a lot. You need some way to make the backpack waterproof. Built-in waterproofing is better, a rain shield is a needed backup plan. (The Setout has the rain shield sold extra; I knew enough to buy it.)
- Make sure there's a separate laptop section, and use it for your electronics. Two separate sections are even better; I put the drugs and travel liquids up front in the front pouch, and the laptop in the back pouch.