Shall we add Darlon and really confuse the issue?
I THINK that there is a difference although I don't know what it is. I have Antron yarn on spools and two kinds of Zelon; straight & crinkled in packages.
I use it interchangeably for trailing shucks although I like the regular Antron yarn & straight Zelon for that better than the crinkled Zelon.
For wings I use neither; I like HiViz.
Darlon - I don't know what the heck it is except that it is finer than all three.