I think COS is generally much better when eyed in person - I've got a 50/50 cotton/poly mix - something on paper I'd avoid like the plague because my general experience with poly fabrics has been they look awful, but it looks fantastic.
Regarding that gradient sweat - caught my eye in the shop the other day as looking really nice, but having a closer look it kind of looked like you had very strange sweat patches.












![shog[1].gif](http://files.styleforum.net/images/smilies/shog%5B1%5D.gif)
Tried it on today and I love it. It's very casual (almost feels like a hoodie) but still minimalistic enough to work in a more dressed up way.