NiB is generally easier to clean after shooting, and not having a black BCG makes it easier to see the residue. IMHO, the action is a little smoother with the coating when it is lubed the same. Not enough to justify doubling the price, but if it were about 10 bucks more, I wouldn't feel too bad about paying a little more.
"Democracy is two wolves and one sheep voting on what to have for dinner.
Liberty is the well-armed lamb contesting the vote." - Benjamin Franklin