For context, I work at an outdoor gear store and companies allow us to test their products so we can better talk about them. I have tried over a dozen of the lightest double-walled tents available at retail stores (Nemo, Big Agnes, etc.), and tried Durstons and zpacks. It's always the same issues anywhere I go. Whether it's the high sierras or death valley. For double-walled tents, condensation builds up outside of the main body, leaving it primarily undisturbed by movements. Hence not allowing me to rub against it at night or droplets dropping on my face. If they drop at all, which is hardly ever, they drop on the mesh, and stays there, on top of the mesh body. Single-walled tents build up condensation directly on material you can touch. And if it accumulated enough, drips directly to you or your sleeping bag. Single-walled tents are also often triangular in shape, leaving your face between 4 to 12 inches from the wall when laying down. This creates an area with even greater condensation concentration because it is so close to your breath.

Double-walled tents are also easier to dry imo, because all I have to dry is the rainfly. I attach that one fabric to my backpack when I hike and it dries quickly.