I'd definitely go large. I'm 5'9" and 150, and I fit medium in almost everything, and this jacket is supposed to be a slim fit. If you want room to layer, get a large.

You sound pretty borderline. The Ferrosi has an athletic cut, but it doesn't really run small. If you are worried, check out the sizing chart (there is a link to it right under the "Options" dropdown box above) and do some basic measurements to see where you'd fit. If you fall right between a M and L (and I suspect you would) then go L for the layering option.

Medium should work....I am 5 9 155lbs to 160lbs and I wear a medium...You are on the cusp of large....My brother is 6 2 180lbs and he wears a large....