I suspect the clicking of metal taps depends on the pieces themselves as well a the cobbler putting them in. I have a pair of second-hand loafers with toe-taps that never make a sound. I love them, so I asked a local place if they could put taps on another pair of my shoes. Unfortunately the taps weren't installed as flush as my in my loafers (they might be a different brand, with a more convex shape?). They tap all the time. So I have one pair of metal toe taps I like, and one I can just tolerate.
If I could get the "right kind" of metal toe taps on all my shoes, I would. I never notice the first pair.
Then again, maybe it just takes a year to wear the toe taps in? They were really slippery the first couple of days. Maybe after a full year they'll get ground into shape. Dunno.
Edit: here's a picture of the two types, for reference. The left shoe is the older loafer with taps that fit seamlessly (silently), and the right shoe has a newer tap that has always clicked. Well, check back with me in another year and we'll see how it's improved.Edited by Makoto Chan - 10/1/12 at 5:41pm