At 6' and 165 lbs, a large fits me perfectly. It does feel a little odd wearing it off the bike, but it's great while riding.
I've worn it in 20-30°F with just a short-sleeve, wool base layer underneath and stayed nice and toasty. Wind?! The wind sees that blue stripe and stops dead. Or at least that's how it feels.
My only complaint is that one time it warmed up a little(45°F!) on my way home and I was too lazy to stop, take it off, and put it in my bag. The result was a very hot and sweaty me after 10 miles of hills. This jacket cannot cure laziness. Yet.