I have not had the Copperhead over the winter yet but I suspect it will hold temp a bit better than the 680 because it is, if not insulated at least double wall construction. I have cooked butts in the Copperhead with no issues at all, its just that I naturally head to the 680 for butts for some reason. It just feels more "natural", I guess. I have had no issues with anything I have cooked on the Copperhead and since it sits under a gazebo I have not had the issues with water that was mentioned on another thread. Overall I am very happy with the Copperhead and I suspect that if I had bought it before the 680 I would only have 1 smoker.