I originally bought this bag thinking I was likely return it. I already own a Side Effect, and even as I pressed the checkout button, I wasn't sure whether it would make sense to have both. And yet. And yet!
This bag has, in the past month, become my favorite bag to carry when I step out for a walk around the neighborhood, to run an errand, or to meet my friends in the park. My phone fits along the side pocket, my wallet (Nik's Minimalist Wallet) and keys clip onto the interior o-ring, and headphones slide into one of the two elastic mesh pouches. With those basics, there's still enough room for an additional set of keys, or a packable tote in case I need to stop for groceries.
My only notes: as other reviews have mentioned, the strap is a little narrow for my liking. I think this bag would be more comfortable if it shipped, by default, with a wider strap. Granted, it's easy to swap out the strap with the one on my Side Effect, so this is less a note about the design of the bag, and more about the provided strap.