I'm a hair under 5'11" and 180 pounds. Normal/average body shape- though wider than average upper body- I cross country ski.
First I got a size medium Expedition Parka based on some of the comments here and it was way too big for me. I exchanged it for size small. Now the jacket fits well. If I was just wearing a t-shirt underneath it might be big, but with long sleeves or a fleece, I think its perfect.- If you are lankier than me I might consider an XS.
I give the jacket 5 stars because the quality is bar none and it is everything I ever wished for. I won't write a long review of pros and cons because there's plenty of reviews out there.
Few words about Canada Goose Chilliwack bomber jacket that I owned for a while. I loved the look of it but never could get used to how it rode up when I leaned over even just a bit. It was just too short for my liking. The sizing of Chilliwack is way different than on Expedition Parka. My Chilli was size large (I tried on M and XL) and it fit well minus the riding up issue but I don't blame the sizing for that.
So the long story short. With my height and weight I would recommend the size Small (maybe even XS if you don't have a wide or muscular upper body) on Expedition Parka and size Large on Chilliwack.