Everybody that passes me with PDW fenders, and everyone does, rattles. I found a set at an estate sale for $3, and have installed them on 2 different bikes with okay results, but I don’t think I’d buy them new.
One noise-cancelling mod I made was to order a set of fender hardware from Handsome Cycles (I think their fenders are called Mud Butlers), and use a few of the parts, like the coated seatstay yoke. These are pretty quiet now.