Don't forget carry options when choosing your Dynamic Inscription System. I exclusively wear 5.11 Tactical Polo shirts, because they are easily the most Operator of all men's casualwear, but mainly because they are issued and required. They feature two rapid deployment writing system holsters on the left sleeve, allowing multiple carry options because two is one and one is none. You can also vary your loadout to suit your theater of operations. For example, when conducting firearms instruction activities, I supplement my aforementioned Free Tactical Bic with a SHARPIE to circle your misses and clearly mark your laughably poor POST Score.
Downside to the 5.11 polo is if your primary hand is injured and you just have to make a note of the fact that yes, it really hurts, you cannot easily draw with your support hand.