The Compressor jacket from Mountain Hardwear is a great jacket. The jacket is surprisingly warm for its relatively light weight, and compacts down to a very small size in the pack. While it is light, some jackets are lighter, but do not offer the same amount of warmth. This jacket is often times in my pack when I go hiking in early spring or in the fall. During winter, I sometimes do bring this jacket along to hike in, because I do not get too hot in it. When at camp in the Winter, it serves as a good layer underneath a heavier jacket. I prefer this jacket to lighter ones in the winter as often the lighter ones don’t have enough insulation in them. This is not a down jacket, so you do not need to be as careful around moisture as with down.