Ernie Sadera wrote a review of Therm-a-Rest NeoAir XTherm Sleeping Pad on February 19, 2014
Familiarity: I've used it once or twice and have initial impressions
This is one WARM pad! I just used this for a winter snowshoeing/camping/ice fishing trip in the BWCA in February. Overnight temps were between 0 and -25F. I slept in a Feathered Friends Ibis Ex 0 bag and the XTherm performed great! I could feel the heat radiating back at me from the pad. For comparison, I tried out my Exped SynMat UL 7 on a 0 degree night and was very noticeably colder. The XTherm wasn't nearly as noisy as I expected and has nowhere near the crinkle of the regular NeoAir. The stuff sack/pump is a little cumbersome. It's not nearly as simple to use as the Schnozzel but it gets the job done. If you're looking for a warm, lightweight, warm, packable and warm pad, look no further! Did I mention it's warm?