I purchased the white shirt in Medium and black one in small, and small is best. I would say go with size you normally wear, I am a 34 chest, and usually wear smalls. The white is also fairly see through, I would not be comfortable wearing it without a tank top or something underneath it. The buttons are are rubbery texture which is nice, but makes it much harder to button on or off. Haven't washed them yet, but I expect them to come out fine. Nice and lightweight.
This review was written in the old system and had content requirements that are different than reviews written today.