This jacket is very impressive. It is cut close and trim for road cycling, which eliminates any flapping. It packs down to the about the size of a standard PBJ sandwich, smaller than a typical SS jersey. It’s extremely lightweight. It functions quite well as a cool-weather wind jacket at road speeds with added wind speeds ranging up to 30 mph (net pushing 50 mph). And in steady light rains it has proven completely waterproof, no breakthrough anywhere, for rides lasting up to ~ 2 hours. The single zippered vent on the right-side back allows you to reach your rear jersey pockets, and extends the comfort range on the high side by allowing for some reasonable ventilation. What makes it even more impressive is it works so well without the typical sweatbox overheating I associate with Gore-Tex jackets. This thing actually breathes, while being as waterproof as any jacket I have ever owned. Finally!
The comfort range depends on air temp, winds, and sun exposure. As a wind jacket on clear, sunny days, it remains comfortable and dry inside with a fall/spring short sleeve base layer (Assos 2.4) and short-sleeve summer jersey (Assos Mangusta) in the range of ~ 50 to ~ 60 °F. In gray, overcast, foggy conditions with steady light rain, moderate winds (6 mph) I’ve found it comfortable and dry with the LS version base layer and same jersey up to ~ 68 °F. I’ve not yet pushed it beyond those ranges on either the high or low side.
The fit is trim, without any excess fabric to flap in the breeze. It’s cut for road cycling in a fairly aggressive position. The size chart worked perfectly for me. All-in all, a superb piece of gear.