This jacket rules. It is much lighter then I thought it would be! The outer fabric is on the thin side but surprisingly durable! I've jumped through trees with it on a lot (I tend to be good at hitting trees) and it hasn't ripped! It is also quite stretchy.
Like I said, it is light! The jacket almost feels like my down puffy coat its so light (given you can obviously still tell a quite distinct difference)
I have other coats that feel much heavier and are restricting on my movement. This on does not restrict movement at all (speaking respectively of course).
The Lining of the jacket has a very soft and puffy feel, and never seems to be too cold when I slip it on. With bare arms, even when I start to sweat, it never begins to get too clammy. Although, I have never tested this in a situation where I am completely drenched in sweat.
It is nice to have a coat that makes it feel like I am hardly wearing anything while skiing. So much more freedom.
The thumb holes were initially a tad bit snug, but they stretched out quite nicely and now fit perfectly. It would also me nice if I was able to get my gloves inside the sleeves, which I cannot. I do have Hestra mitts (http://www.backcountry.com/hestra-heli-mitt) and the cuffs are, compared to some other gloves, gigantic. I suspect that with a more slender pair of gloves, such as the Black Diamond Legend Glove ( http://www.backcountry.com/black-diamond-legend-glove-mens ) or the Hestra Ski Cross glove ( http://www.backcountry.com/hestra-ski-cross-glove ) (Links given so you can easily see the cuff type I am talking about), you could get the cuff inside the sleeve and still where the thumb loops without too much difficulty and it would continue to be comfortable.
The Cirrus insulation definitely gets the job done. I haven't yet been could and I have been in 15 F degree weather with some wind. If you were to put it on inside at a friendly gathering or royal ball perhaps, you would probably want to leave fast, or you may be in danger of become considerably warmer and beginning to sweat. No one wants to sweat at a royal ball.
I am 5'8" and 160lbs with an athletic build. And the medium fits like a soft and fluffy lucid dream.