I've owned this jacket just over a year. I wear it everyday from October -March. It is the perfect piece for cold commuting on a bicycle and chilly days to the craig.
I was very skeptical of the Coreloft insulation before I had purchased the jacket, and now I am a believer. It regulates with your body temperature very well. Not quite as good as premium down, but it still works amazingly.
Thinking back on it, I wish I would have gotten the hooded version, but this piece is very nice, but it also passes for looking like casual jacket.
Don't get me wrong, I'm a huge gear whore, but I don't feel the need to have every jacket look like I'm geared up to Summit K2 when I'm going out to dinner.
For sizing, I'm a pretty thin guy. 6'0, 135lbs with an even ape index. And I think it fits very nicely. It's hard to find a medium that actually fits these days.
The only thing I would add would be elastic waist tensioner so the bottom was more form fitting to my actual waist.