I typically a skeptic with everything. And I read a few reviews on some other Castelli products that weren't all that great but I figured, This one looks good and the features are appealing so I'll give it a shot. I can honestly say, It was worth the money. Everything about it is quality, from the wind resistance, fleece lining, stitching, whatever...
I rode all last winter in temps as low as the 20's and my upper body was nice and comfy. I Can't say the same for my feet though but I'm working on that.
As for the sizing, I am not the smallest guy. I'm not fat either. I wear a size 40R formal suit and large T shirts so I bought a large Jacket and It fits like a riding jacket should, Like it was tailored for me. No extra fabric flapping in the wind but not so tight I can't move.
Bottom line, I would recommend this jacket to anyone.