Bought the medium which is a relatively snug compared to a lot of mountain biking jerseys but not in bad way. The fit still allows for plenty of movement. Slightly heavier weight fabric than I was expecting which has a quality feel to it. I would be happy wearing it as a long sleeve tshirt off the bike. My only very slight niggle is that the cuffs are quite slim meaning that it isn't really possible for me to push the sleeves up in warmer conditions.