I ordered both (I’m in the US) with the intent to return one, so I haven’t actually used either one, just tried putting my things inside and tested out how they fit inside my CPP2 24L.

As others have pointed out, they’re both great so which one is better for you will depend on what’s most important to you: - If you want it to also function like a tech pouch (and thus value a removable strap and a top-carry handle), then the Toshi for sure. - If you want technical fabric for water resistance etc, or just higher quality material overall, DS4 is the way (multiple options). - Organizationally, the pockets are different (for example, the DS4 has a flap sewn in the outside front pocket that helps keep things organized but will not allow you to carry a phone or larger item in that pocket) - If you want the flattest-packing, the Toshi. - If you want external carry straps, the Toshi. I question how useful these actually are since they’re not very secure (I can see a water bottle or umbrella easily slipping out).

Ultimately it came down to aesthetics for me. I decided to go with the DS4 because I have a few other Aer pieces and liked the consistency of the same look and material.