Looking at picking up one or the other soon and can't decide which. Only going to be getting the shirt. Can anyone give me any sort of idea of the difference in warmth. The mid-weight is almost $30 bucks cheaper, is it still very warm? Anybody got both or tried both that can tell me about which one you pick in certain temps? Does activity level matter? I do everything from all day sits in the 20's and 30's, to very long hard walks when duck hunting. For the average guy on a budget, is the expedition weight worth dropping $90 bucks just for the top?