I'm getting back into reloading after about a 12 year hiatus and looking at what components are out there. Fortunately, I own a 10mm which doesn't seem to be overwhelmed with demand like 9mm is. It looks like cast lead bullets are the cheapest that you can get but for about 5% (or so) more money you can get polymer coated bullets. What's the advantage of these? Easier cleaning of the gun? Less lead in the air when you shoot? Something else?