This thermal long sleeve is great for cool mornings or as one of your winter layers, depending on how cold it gets where you are.
The brushed fleece and long sleeves offer more coverage than a vest and a softer feel and more breathability than most jackets. Use it on its own, as a second or third layer over your base layer or summer jersey.
Personally, I hate baggy sleeves that flap in the wind. This jersey is just tight enough not to feel bulky, but has enough stretch to flex and move as you wear it.