I got a small. I'm 5'8", but with a slightly longer torso, 155 lbs, 30-31 waist, and about 39 chest. The small fits fantastically, snug, but with enough room for a warm base layer if I want. The jacket is great: very warm, light, durable, looks good, comfortable. Since it's OR, it comes with a lifetime warranty too, which is always great in case you run into trouble later on.
The only problem I think is the hood, it's a little bit awkward. It's very warm and functional, but looks-wise very tight fitting and weird when up. I suppose this may be so you can fit a helmet over it, I'm not sure. I'm not really concerned with looks in a jacket that I buy for function not fashion, but it's just a small note. It's also more expensive than it really should be for a fleece jacket, but you could say that about all high quality fleece jackets, and I got this one for a great deal on S&C.