My Castelli Corsa winter gloves never really fit me well which probably contributed to my cold hands. Riding thru the upper mid-west winters, I needed a glove that would work down into the upper 30's and fit better (colder than that and I switch to my lobster claws). After comparing all the choices, I went with the Castelli Espresso GT. They fit much better and are definitely warmer. I like the zipper closure and have had only minimal issues zipping them closed. Once closed they feel very secure with no cold air ingress noted. Would buy again.
Most of my rides start at 9:00 AM as long as the temperature is 35 and up and sunny or 40 and cloudy. I'm an older rider and keeping my hands warm is necessary. These gloves supplemented with a liner handles my needs well. At about 45 the liners have to come out and at about 50 they start getting too warm and at 55 they are too warm.
Use for 30-40 degree days of biking plus basic gloves in a non-athletic setting. The fingers feel like they could be slightly better insulated. I therefore use these on cold days but not below 30, at least not for long rides.