It has been suggested by people whose ears I trust more than mine, that nylon/? any fabric pop filters scrub off some highs, and that steel does less of that. I can't hear the difference, but that's my old ears. As you lose your ability to hear highs, you make more use of the ears of people you trust. I'll tell you this, though, for sure- Metal pop filters don't get "runs". They aren't automatically destroyed when some drunk Death Metal rocker butts out a cigarette on it, and of course, then blows smoke into the (hopefully his) main vocal mic. Steel pop filters are more roadworthy, and in a live setting, they can be good on a flute, or any breathy wind instrument. This business of scrubbing off the highs- It's a pretty small difference, but it depends on whether you think the singer sounds better, or worse, with a low pass filter. Some singers that are shrill need that. I use steel because it is durable.-Richie