Great on returns but charge shipping on the return as well as potentially on the exchange.
My advice, call them, and ask about sizing, tell them you are torn between two. They will make a recommendation. At that point, say, "If it doesnt work out on the size, can you help me out with shipping on the exchange, I've had to exchange a few things in the past and the extra shipping fees are a killer".
I have done this twice before ordering and ended up needing to exchange, and it cost me nothing.