I bought this for my husband. He's incredibly jealous of my own merino sweater, and I have been scouring the interwebs for his since he gave me mine. SO:
The fit is nice on this sweater, and the wool is soft. I'd call it a light/medium layer. Think: walking around early fall or in the spring, with this as your top layer. A little colder weather if you're wearing it on the trail. I don't feel like it has the lasting capacity to take heavy hiking, but I may be wrong. I bought him a medium, which is his standard, and it had a little extra room.
I'm not a huge fan of the clunky zipper, particularly on the pocket. But the reason that I'm returning it is the color: We're looking for the best dark brown merino sweater there is, and unfortunately the "bark" color is more like "dark eggplant." I mean, its PURPLE!