I have had great success with the screen cover on down lighting products far and away better than any lensed fixture. Granted, we don't have the kind of rain that travels vertically and upwardly, but we probably get more rain than most on this forum anyway. Downlights/Moonlights are probably the least troublesome fixture locations that we get called for and I agree with Tim....... If it has a lens, it's getting knocked out before it goes into one of my projects. I tend to rely on time tested results more than anything else. IP ratings, or any other rating for that matter, mean very little to me; however, you can make that kind of thing sound very fancy during a sales presentation. My suggestion would be to use the technical terms when talking about it, then go install what has been proven to work.