Was looking for something between a vest with arm warmers and a full winter jacket. This is perfect for me between 45 and 55 F, along with a Craft long sleeve base layer (I have comfortably worn down to 40 F on a calm day). Wind front works well to keep warm without the bulky insulation of a jacket. Seems to breathe well and the zippered vents in the sleeves and the sides are a nice feature as the temp warms up. I had an early version of Xenon short sleeve jersey and found the fit too loose, but this Medium jersey fits very well - snug but not tight (I am not built like a racer - about 5' 7" and 155 lbs.). Even the slanted pockets work very well. Overall very happy with this jersey.