Ditto on the Exped Downmat. I've used mine in some early, springtime temps that were really too warm and humid to be using it in, and I don't recall it causing my back to sweat. I did have to let some heat out though, and vented my quilt, but I don't remember sweating. They have a nice texture. I have a short and a long version. I like the way the shorter one seems to fit in the middle of my A-sym hammock and lets you lay a little flatter than normal, where the long is a little more difficult to position yourself on. They fit perfectly in a JRB BMB to.