I first bought a Large as that is my size on every other shirt I've ever bought. Had to exchange it for an extra large which fits almost perfectly. I like the way it wears and is very comfortable. Trust me order one size larger than you would normally wear.
I am not a big guy - 5'10", 170 - and I have many cotton and Taclite Tactical shirts (long and short sleeve). They all fit a little large with comfortable room to spare. Not so with these shirts. The "Updated fit" means the shirts fit me perfectly but sometimes I feel a little tightness in the shoulders. If you're bulky or muscular you should be very careful about sizing. I think they're great for me (hence the 5 stars), but others may have real issues.
This shirt is cut extremely small. I normally take a medium shirt (5'10" 160 lbs) but this shirt fit like a small to extra small. Will take it back to the store in Salt Lake this weekend. Wish the other Stryke shirts came in a dark brown like this one is.