Not going to argue, but I am convinced that it's generally true that stainless valves are lighter, stronger, and more durable than their OEM counterparts. There are no doubt exceptions on the stainless side, as well as the OEM side. The question was general, regarding why stainless? That's my story and I am generally sticking to it
http://www.sivalves.com/ocdomestic_valvesss.html
John