Like Tyler said the sizing on these shirts is a little off for the common man. In order to have enough room in the armpit area to move your arms comfortably you have to get a size the feels too big in all the other areas of the shirt. If you're tucking the shirt in then it's not such a big deal, but if not then it feels a bit too big.
It's also worth noting that these shirts are DRY CLEAN only.