I have many cycling jackets from good manufactures such as Gore and Showerpass but this is by far the best cycling jacket I have owned. The jacket is well made and very very warm. I've used this jacket in conditions of 35 degree F up to 47 degree F with just a base layer. I could probably do without a base layer but want a layer to catch sweat. If you ride hard your back will sweat. There is just no getting around it. Even still, you stay warm.
Venting is great. Front zip vents work great for just enough airflow that does not make you cold. They are a little hard to zip while riding but I manage to find them without crashing. The jacket's construction has shoulder vents that are open through the whole back. What Ii mean is, you can put your hand and arm in the shoulder vent and it will go through to the bottom of the jacket between the jacket liner and fleece. I first thought that, with the shoulder vents always open, I would get cold, but I did not.
Overall I am sold on the Windstopper fabric. Windstopper takes the wild chill factor out of the ride equation. I feel zero wind on my upper body now when riding.
This jacket is a tight fit by design. I am a skinny 6 foot 145 pound guy and I choose a large jacket. I could have fit in a medium but wanted a little room in case I wanted to put more than one layer under it for extreme cold conditions. I also have broad shoulders and I thought the medium would be too small in this area. The large fits perfect through the shoulders.
I used to hate riding in the cold but now I dont mind and even choose to ride outside in the cold instead of using the indoor trainer. Hope this helps you decide. Have a great ride.