I was hoping someone else would answer your query since I'm in the business and don't want to appear as if I'm trying to promote same on this forum.
However, since no one's jumped in in the past eight hours or so, I'll take a small (as in "short") stab at it.
In my experience any type of coating that is applied by either dipping or spraying and then "baked" on does two things:
1. It protects very well against the elements, against salt, in general against corrosion.
2. It is very susceptible to abrasion from sharp objects. Moreover, sharp edges on the arm will undoubtedly wear thin on repeated contact with leather and the like.
The above applies to virtually all the coatings out there, including Black-T, GunKote, Roguard, GnomeKote -- just about all of 'em. This isn't to say they're bad finishes, 'cause they aren't -- they really do protect the gun from rust and corrosion, which is what they're intended to do, much more so than bluing or the like. But, like bluing, they tend to show wear and tear which, to some people, is anathema. Those who live with the gun as a tool, however, generally tend to overlook such esthetic problems in light of the overiding benefits provided.
Plating generally tends to be quite a bit tougher, but it looks like....er...plating! And, if something does pierce plating's surface, the entire item generally must be stripped to reapply the plating. The teflon/molybdenum/whatever finishes can usually be reapplied directly over the previous finish with no degradation.
Anyway, a short bit of one person's insight into the situation. Opinions vary, just like your mileage (grin).