I am 5'8" 190 and I went with the large. It is long in the sleeves but fits well around the chest and is loose around the stomache. A medium fits me as well but is a bit too tight in the chest and arms. This is more relaxed fit than most of their other pieces. On their website it is listed as relaxed fit where as most the other fleece are listed as athletic. I would have a hard time seeing the length of the arms of a L fit you at 6'3". I would think an XL would be a better fit.

I'd go with the Large as well. I'm 5'6 and 150 and I went with a medium...the small was just a tad too short all around. The medium is maybe a little bigger than I'd like, but still an athletic fit on me. Given the size difference between us, I think the medium would fall short on you.

I'd go with a Large...I'm 6' and 170 and have a Medium and it's just about the right length in arms/torso...maybe a little tighter than I'd like.

I'd say Large, but you should check the sizing chart.