This particular product should not be characterized as clothing but as a Tool.
It keeps you warm without sweating, it doesn't let the air in, the pertex material makes the difference, it is extremely lightweight and has a carrying pouch that takes up no space at all.
Truly excellent for both the mountain and casual wear.
Unfortunately, I burned it on the sleeve last year, sent it to England, and it came back brand new...
The only negative is that once you put it on, you don't want to take it off again...