Answer I haven't tried Icebreaker. I am 6'0 with 34'' sleeves, 175lbs, athletic frame, and the medium fits me great. I usually have to look for brands with longer sleeves as well. This jacket fits well though. I can wear it while using the thumbholes and it is still comfortable. A large would give a little more room in the sleeves, but then it wouldn't fit very well in the chest.
Answer I am 6'2 and 215lbs, athletic build with 34" waist and 34/35 sleeves. I chose the L and it fits me perfectly. I would recommend the medium, but must admit that I have no experience with other sizes of Smartwool products. I just always buy L. I usually wear an XL with Icebreaker. Hope that helps!
Answer I'm 5' 7" ~160lbs and a Med is a perfect fit. I would go Large.