In reply to Marek:
I spend a lot of my youth swimming, and thus my shoulders are *fairly* broad. Not huge, but certainly not small. I can't wear buffalo for example. I find the Boreas Pull-On to fit me fine. The sleeves are a touch long (I've got a negative APE index) but it just helps keep my hands warm, and the elasticated cuff keeps itself on my wrist if I want it there.
In terms of the breathability, I've used mine running and I'm sweaty as hell. It dealt with it fine.
I wouldn't describe it as windPROOF but pretty wind resistant. I'd also agree with the person who said it's a 2-3 season top. It's not massively warm, but for Spring through to Autumn I wear it on every trad route I do. That also explains how it's "highly breathable".
Finally, I've never considered the need for it to pack away into it's pocket as I just leave it on all day, but the suggestion of the 2mm cord sounds like it would solve that issue.