For anyone who spends the night in a tent (or bivouac sack) in the mountains in winter, the sleeping mat is practically just as important as the sleeping bag. As you are basically lying on cold ground (snow) and the warm sleeping bag is compressed by your body weight and therefore provides practically no insulation, you need a mat that insulates as well as possible to keep heat loss to the ground to a minimum. Until recently, thick foam mats were therefore usually used for winter camping. Although these are warm, very reliable and inexpensive, they are not necessarily comfortable and light, not to mention the pack size. In recent years, however, this has changed dramatically and there are now inflatable mats with down or synthetic fiber filling, as well as the Neoair series from the renowned manufacturer Therm-A-Rest. With these mats, one (or more) reflective foils keep the air and warmth in place. The warmest model in the series, the Neoair Xtherm, is fully suitable for winter use with very high insulation (R-value 5.7 according to the manufacturer).
I've been using the mat for some time now. In addition to summer and winter in the Alps, I also used it on a Cordillera Darwin expedition, where it served as a base for two weeks at a time. The very low weight and pack size (especially in comparison to the insulation performance) of the mat are striking as soon as you unpack it. It weighs less than half a kilo and is smaller than a 1L Nalgene when rolled up. This puts it well ahead of all competing products. The same cannot be said for comfort. I sleep very well on the Neoair and find it comfortable enough, especially when it is fully inflated. However, it doesn't quite give you that "bed" feeling like some thicker (and of course noticeably heavier) mats with down or synthetic fiber filling. As it does not have an integrated pump for weight reasons, you have to inflate the Neoair by mouth (a pump bag is included, but if you use this you will probably only get into bed or onto the mat towards dawn), but in my experience this is not a problem and can be done in a maximum of two minutes. Initial concerns about the robustness of the outer material of the mat, which is very plastic-like to the touch but also very non-slip, have now been dispelled. Of course, especially on longer trips away from civilization, you should bear in mind that even a small hole in the mat can result in a virtually complete loss of insulation! A repair kit is included with the mat, but fortunately I haven't had to test this yet.
I am 183 cm tall and use the mat in size Regular, which is not exactly generous. However, I use my backpack, rope or whatever else is available as a pillow, so it fits well. However, you should be aware that the dimensions of the mat are designed for lightness rather than luxury.
Conclusion
Warm, comfortable, compact and light. You can't ask for more from a mat! The only downside is the rather high price...
