I use one, the Klymit Static V(the green one) and they are very comfortable and light under certain conditions. When the ground is frozen or snow covered they become somewhat uncomfortable. You have to remember unlike Thermorest these little guys have only air between you and whatever you are sleeping on. On a six nighter ,early in October,this past hunting season I camped in 25cm of snow with temperatures down to -10 or -12C at night, since we were staying in the one camp so long we placed spruce boughs under the tents to get them up off the cold ground and I was very comfortable. On an weekender later in October under similar conditions I didn't bother and the cold from under me became a problem plus on top of the sleeping pad I had a lot of water droplets due to condensation. They are great in the warmer months but once temperatures start to drop a little extra padding is in order. Where I hunt and backpack a few spruce boughs are usually readily available but above treeline or in a more sensitive area I would want something with a little padding in it.