This is my first Fayettechill product, and I really like it. It's soft, feels high-quality, and is responsibly-made. I will say, I got it at a steep discount and that's probably the only time I will buy their products. I can't bring myself to shell out their sticker prices for something that's still just a t-shirt at the end of the day. Original pricing is what knocks off a star.
As far as sizing goes: I'm a 5'6, 125lb female and the XS fits me comfortably (not tight); it's a muscle-shirt on my 5'10, 165lb husband.