I really like this vest. It lets a small amount of air though for cooling so it is not completely wind proof, and it works well. It packs down small, and has enough stretch to a snug fit that is true to size. If it had a two way front zip andor an easy access point to a rear pocket would make it 5 stars and those are minor grips for a great vest.
This Castelli vest fits great and capably fills the wardrobe gap when you need some light protection from the elements. I've used the Superleggera now several times, over just a springsummer jersey w arm warmers when 45-55 degrees, and its a perfect layering option. I'ts light weight and packs well when its time to shed a layer. I have also used this vest when running. There are no pockets, which is worth knowing prior to purchase, but has not proven to be any problem. Even with a somewhat trim fit, there is sufficient room to stuff your jersey pockets under the vest. I love this vest!