Air mattresses are certianly comfortable, but they are COLD, plus the pop, and they are heavy. If you are going into the high country when it's cold out, I would suggest a cot. They get cold too, but you can stuff gear under them to help retain a little body heat. I like a cot with a small egg foam mattress (they weigh nothing). It is reasonably comfortable and does not get as cold.

Did I mention to put as much stuff under your cot as you can? Keep that air from moving around underneath you.