Check with the manufacturer to be sure but I think the valiant will be polyurethane (not necessarily a bad thing and better than pvc). Not sure about the joker. Joker is a much smaller brand so at resale may be less well known. Ideally you would get sea trials of both in conditions like those you will use them in. In terms of longevity it will depend how you look after them, Amy boat which gets cleaned and stored indoors will fair better than one left bobbing up and down on a moorings 24/7 getting shat on by seagulls.