I tried the large and was surprised that it was so tight in the arm pits. No better than the medium. It did have more material in the middle far upper back close to the neck, but that wasn't where I needed it.

Overall, the Intelliskin is a no go for me. I think if they did custom shirts where they measured out your shoulder, chest, upper traps, etc., and then cranked out a shirt for your body, it would work great. I believe it will also work great if you are fortunate enough to have a good fit with their existing shirts. Sadly, that is not the case with me.

jkl626 mentioned that they liked "The Spinal Q Brace". Um, wow, looks hard to order: http://www.spinalq.com/ (web site comes up blank under any browser at this time).