A great light jacket, just a little tight around the armpit - Marmot ROM Jacket - Men's

I'm 5'5" and 140 lbs, and the size small fits me well (it has an athletic fit). Since it has an athletic fit, if you plan on wearing multiple layers underneath, you might want to consider getting 1 size up. I think the length of the sleeves is good, especially with the adjustable velcro cuffs (for reference, my dress shirts at work are 32"); I recently bought a The North Face (TNF) Apex Bionic 2 jacket, and the TNF sleeves were way too long for the size small jacket. The area around the armpit (from the bottom of the armpit to the top of the shoulder) is a little tight, which might become a concern if you plan on wearing a mid-weight base layer underneath; however, the fabric has some stretch, and since I only plan to wear a light, moisture-wicking t-shirt underneath, it doesn't bother me too much.