1. There is not stretch material around the cuffs. if it gets windy and you only have this on you, the wind will get in easily. it also have breathable material all the way from the side of your body to the end of the sleeve, which is nice if you are doing high output activity. 2. Even though it has coreloft 80 (compared to Atom LT's Coreloft 60), I don't believe this jacket would be any warmer/toastier than Atom LT due to the items mentioned in 1. Unless you have an outer shell that helps with wind blocking. 3. It fit is a bit more relaxed than Atom LT, and overall cut is longer.