Okay, so looking at these jackets and I'm curious as to why they mostly are duck down, from what I've seen only the snow mantra is actually goose down, they also seem like low fill power since they are around 650.
What's the reasoning behind this?

Secondly, if I was to buy a canada goose jacket, would I just be sweating constantly in England, since it really doesn't get that cold here?
Not going to lie, I really want the snow mantra.