Poncho's strengths are packability, usefullness in building or extending a shelter and universal size. Their weakness is if you do heavy work or scrambling over obstacles you will eventually get wet. You have to work REAL hard at overheating in a poncho. Coated nylon is very waterproof. It can eventually lose partial coating through use and washing. You could also look into the various oiled clothing such as Barbour, Filson and Australia's Drizabone. These are fine cotton dressed in a wax/oil finish that can be renewed much like shining shoes.