I like the plastic helmet-steel veil combination BUT, after a few years, the droplets of sweat that land on the metal cause them to rust through and break. That doesn't happen with the nylon-screen veils, which as a result, last much longer and make them a better investment.
Truth be told, I've pretty much given up using the helmet-steel screen veil combination since I find it so much easier to quickly don my hooded jacket with the nylon screen and get to work in half the time it takes to dress up with the plastic helmet arrrangement.