While the t-shirts are soft and great quality, they were smaller than anticipated. My husband always takes a large, but an extra-large would have been better. Same thing for me: I take small, but a medium would have been more comfortable. My advice? Order a size up.
I got a woman’s small. It just fits me, so I’ll have to be careful not to shrink it, however it has enough stretch that it’s not uncomfortable in the arms or anywhere, so I’m not unhappy with it. It’s super cute!