light, comfortable, easy to deploy -- just unfold it to use and fold back up to put away. I use it in snow and mud to keep myself warm and dry when I need to sit for something or just want to take a lunch break. It's nice that you don't have to worry about puncturing it or popping it with sparks from a fire or stepping on it with crampons which has been done multiple times and the pad is no worse for the wear.
bulky when packed, but it fits into water bottle holders on a pack well
I cut a $2 foam mat, from the swim dept. at WM to fit my butt. lighter/cheaper/same function. Or you can just go green and use a recycled USPS Tyvek envelope.It weighs even less and folds smaller.
